Health Consultation

Evaluation of Non-Hodgkin’s Lymphoma, Prostate Cancer, Stomach Cancer, and Thyroid Cancer Incidence in Watertown, Massachusetts and Adjacent Census Tracts

1982-1994

Prepared by:
Massachusetts Department of Public Health Bureau of Environmental Health Assessment Community Assessment Unit
Boston, MA

Under a Cooperative Agreement with: Public Health Service
Agency for Toxic Substances and Disease Registry US Department of Health and Human Services Atlanta, GA

June 7, 2002

Evaluation of Non-Hodgkin’s Lymphoma, Prostate Cancer, Stomach Cancer, and Thyroid Cancer Incidence in Watertown, Massachusetts and Adjacent Census Tracts

TABLE OF CONTENTS

I.          INTRODUCTION............................................................................................................................................1

II.        SITE BACKGROUND ....................................................................................................................................3

III.       OBJECTIVES ..................................................................................................................................................4

IV.       METHODS FOR ANALYZING CANCER INCIDENCE DATA ..............................................................5

A.         CASE IDENTIFICATION................................................................................................................................... 5

B.         CALCULATION OF STANDARDIZED INCIDENCE RATIOS (SIRS) .................................................................. 7

C.         EXPLANATION/INTERPRETATION OF AN SIR ............................................................................................... 8

D.         CALCULATION OF 95% CONFIDENCE INTERVAL......................................................................................... 9

E.          DETERMINATION OF GEOGRAPHIC DISTRIBUTION .................................................................................... 10

F.          DEMOGRAPHIC ANALYSIS........................................................................................................................... 10

G.         EVALUATION OF CANCER RISK FACTORS................................................................................................... 11

V.         RESULTS OF CANCER INCIDENCE ANALYSIS  .................................................................................11

A.         CANCER INCIDENCE IN WATERTOWN..................................................................................................... 12

B.         CANCER INCIDENCE IN BRIGHTON/ALLSTON......................................................................................... 16

C.         CANCER INCIDENCE IN CAMBRIDGE....................................................................................................... 18

D.         CANCER INCIDENCE IN NEWTON............................................................................................................ 19

VI.       EVALUATION OF CANCER RISK FACTOR INFORMATION...........................................................20

A.         NON-HODGKIN’S LYMPHOMA................................................................................................................. 21

B.         PROSTATE CANCER.................................................................................................................................. 25

C.         STOMACH CANCER.................................................................................................................................. 27

D.         THYROID CANCER................................................................................................................................... 30

VII.      EVALUATION OF GEOGRAPHIC DISTRIBUTION ...........................................................................31

A.         WATERTOWN.......................................................................................................................................... 32

B.         BRIGHTON/ALLSTON, CAMBRIDGE, AND NEWTON.............................................................................. 33

VIII.    COMMUNITY ENVIRONMENTAL CONCERNS .................................................................................33

IX.       DISCUSSION.................................................................................................................................................35

A.         NON-HODGKIN’S LYMPHOMA................................................................................................................ 36

B.         PROSTATE CANCER.................................................................................................................................. 38

C.         STOMACH CANCER................................................................................................................................... 40

D.         THYROID CANCER.................................................................................................................................... 41

X.         CONCLUSIONS ............................................................................................................................................42

XI.       RECOMMENDATIONS................................................................................................................................43

XII.      REFERENCES ...............................................................................................................................................44

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LIST OF FIGURES

Figure 1:           Location of AMTL, Watertown, MA

Figure 2:           Study Area Census Tracts, AMTL Region

Figure 3:           Distribution of Smoking Status for Watertown and Massachusetts

LIST OF TABLES

Table 1:            Demographic Statistics for All Census Tracts

Table 2:            Cancer Incidence, Watertown, Massachusetts 1982-1986 and 1987-1994

Table 3:            Cancer Incidence in Census Tract 3701, Watertown, Massachusetts 1982-1986
and 1987-1994

Table 4:            Cancer Incidence in Census Tract 3702, Watertown, Massachusetts 1982-1986
and 1987-1994

Table 5:            Cancer Incidence in Census Tract 3703, Watertown, Massachusetts 1982-1986
and 1987-1994

Table 6:            Cancer Incidence in Census Tract 3704, Watertown, Massachusetts 1982-1986
and 1987-1994

Table 7:            Cancer Incidence in Census Tract 1.00, Brighton/Allston, Massachusetts 1982-
1986 and 1987-1994

Table 8:            Cancer Incidence in Census Tract 2.01, Brighton/Allston, Massachusetts 1982-
1986 and 1987-1994

Table 9:            Cancer Incidence in Census Tract 2.02, Brighton/Allston, Massachusetts 1982-
1986 and 1987-1994

Table 10:          Cancer Incidence in Census Tract 3.00, Brighton/Allston, Massachusetts 1982-
1986 and 1987-1994

Table 11:          Cancer Incidence in Census Tract 3542, Cambridge, Massachusetts 1982-1986
and 1987-1994

Table 12:          Cancer Incidence in Census Tract 3543, Cambridge, Massachusetts 1982-1986
and 1987-1994

Table 13:          Cancer Incidence in Census Tract 3731, Newton, Massachusetts 1982-1986 and
1987-1994

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I.         INTRODUCTION
In 1996, the Massachusetts Department of Public Health (MDPH), Bureau of Environmental   Health   Assessment   (BEHA),   released   a   health   consultation   for Watertown,  MA  (MDPH  1996).    The  health  consultation  was  conducted  under  a cooperative agreement with the U.S. Agency for Toxic Substances and Disease Registry
(ATSDR) and was completed at the request of several citizens' groups and legislative representatives   from   Watertown   who   petitioned   ATSDR   to   evaluate   health   and environmental concerns.  The primary community concerns focused on the possibility of a relationship between cancer incidence and environmental exposures associated with the presence of the Army Materials Technology Laboratory (AMTL), which is on the U.S Environmental Protection Agency's (EPA) National Priorities List (NPL).  The NPL is EPA's list of uncontrolled or abandoned hazardous waste sites identified for   possible long-term remedial action under the Federal Superfund.

In response to these concerns, MDPH reviewed the incidence of twelve cancer types for the years of 1982-1990.  These cancer types included Hodgkin’s disease, non- Hodgkin’s lymphoma, leukemia,  and cancers of the bladder, brain, breast, kidney, liver, lung, pancreas, stomach, and thyroid (MDPH 1996) and were evaluated for Watertown as a whole and for each of the four census tracts that further subdivide the town (CTs 3701,
3702, 3703, and 3704).  Census tracts 3703 and 3704 are located adjacent to the AMTL site, a former arms manufacturing, storage, and materials research facility (see Figures 1 and 2).

The results of the 1996 health consultation revealed that Watertown as a whole did not experience statistically significant elevations for the twelve cancer types that were analyzed.  Statistically significant elevations in individual census tracts, however, were found.  The statistically significant elevations in specific census tracts were as follows:

-     Bladder cancer in CT 3701 for males and for males and females combined.
-     Non-Hodgkin’s  lymphoma  (NHL)  in  CT  3704  for  males  and  females combined.

-     Stomach cancer in CT 3704 for males and females combined.

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-     Thyroid cancer in CT 3703 for females and for males and females combined.

In  addition,  the  consultation  noted  that  diagnoses  for  certain  cancer  types appeared concentrated in Watertown, including bladder cancer cases in CT 3701, NHL cases in CT 3703, and stomach cancer cases in CT 3704.  Census tract 3701 is located on the western side of Watertown and is not near the AMTL site.  The NHL cases in CT

3703 were also not located near the AMTL site.  The stomach cancer cases in CT 3704

were located in a neighborhood near the AMTL site.

As a result of the 1996 Health Consultation, the MDPH/BEHA recommended a further evaluation of risk factor information and residential histories for the cancer types that appeared concentrated in Watertown.  This work was completed in January 2000. The  results  of  this  analysis  did  not  reveal  any  unusual  patterns  that  suggest  that environmental  factors  played  a  role  in  the  occurrence  of  several  types  of  cancer  in Watertown census tracts (ATSDR 2000).

In addition to the follow-up work recommended in the Health Consultation, the Watertown AMTL Restoration Advisory Board (RAB), a committee established to help select the best remedies for restoring the site and to ensure community participation in this process, separately requested that the MDPH/BEHA update cancer incidence data for three cancer types NHL, stomach, and thyroid.  The RAB also requested that prostate cancer be added to the updated investigation.  The RAB raised concerns about these cancer types in Watertown, and in additional areas adjacent to and across the Charles River  from  Watertown,  including  Brighton/Allston  (CTs  1.00,  2.01,  2.02,  and  3.00), Cambridge (CTs 3542 and 3543), and Newton (CT 3731).

The locations of these census tracts in relation to Watertown and the AMTL site are depicted in Figure 2.  In response to the RAB request, this report summarizes the additional analyses of these four cancer types in Watertown and adjacent census tracts in Brighton/Allston, Cambridge, and Newton.

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II.        SITE BACKGROUND
The   AMTL   property   is   located   on   36.5   acres   of   land   in   Watertown, Massachusetts, approximately five miles west of downtown Boston.  The former mission of  AMTL  was  materials  development,  structural  integrity  testing,  solid  mechanics, lightweight armor development, and manufacturing testing technology.  The facility was established as the Watertown Arsenal in 1816 and was originally used for the storage, cleaning, repair, and issue of small arms and ordnance supplies.  During the 1800s, this mission was expanded to include ammunition and pyrotechnics production, materials testing,  and  experimentation  with  paint,  field  and  siege  guns.    Arms  manufacturing continued at the facility until an operational phasedown was initiated in 1967.  In 1960 the army constructed its first materials research nuclear reactor, which was used actively in molecular and atomic structure research activities until 1970, when it was deactivated. In September 1995, the AMTL was closed upon recommendation from the Secretary of Defense’s ad hoc Commission on Base Realignment and Closure (ATSDR 1997).

Environmental  investigations  conducted  at  the  AMTL  site  subsequent  to  its closure detected contamination at the property.  Therefore, the AMTL site was proposed to the NPL in June 1993 and added to the list on May 31, 1994.  Contamination in soil
(e.g., metals, pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbon compounds) and groundwater (e.g., chlorinated solvents) beneath the AMTL site and the potential for site contaminants to migrate to the Charles River were factors in considering the site for the NPL.  Specific environmental concerns focused on the potential for human exposure to contaminant releases from the site.

The Federal Facilities Assessment Branch of ATSDR prepared a Public Health

Assessment (PHA) of the AMTL site that was released on February 21, 1997 (ATSDR
1997).    The  PHA  evaluated  opportunities  for  exposure  to  site-related contaminants. ATSDR concluded that opportunities for exposures to site-related contaminants (e.g., from past air emissions of depleted uranium) were not expected to result in health effects. For further details on ATSDR’s assessment of environmental data related to the AMTL, see the PHA (ATSDR 1997).

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III.      OBJECTIVES
This investigation is a descriptive evaluation of health outcome data for cancer. The primary focus in this report is to review cancer incidence for Watertown as a whole, and for the additional census tracts in towns adjacent to the AMTL.  The intent of the investigation was to evaluate the temporal and geographic pattern of cancer in these areas, and the possible role that risk factors, including environmental factors, might have played in cancer incidence in this area.

Descriptive analyses of cancer incidence may indicate a pattern that suggests a common etiology is possible and can serve to identify areas where further public health investigations or actions may be warranted.  Descriptive analyses may also help identify an excess of a well-established risk factor that is associated with a disease in a certain geographic area.  However,  descriptive assessments have certain inherent limitations. Only routine data collected at the time of each individual’s cancer diagnosis are analyzed and information about personal risk factors (e.g. family history, hormonal events, diet) that may also influence cancer incidence is often limited and is not of historical nature. Therefore, it is beyond the scope of this investigation to determine any causal relationship or synergistic roles that risk factors (environmental or non-environmental) discussed in this report may have played in the development of cancer in the Watertown AMTL study region.  The purpose of this investigation is to provide a comparison of the incidence of the cancers in Watertown and adjacent census tracts with the incidence of these cancers in the state of Massachusetts, and to report and discuss findings in the context of the available information to determine whether further investigation is warranted.

The specific objectives of this investigation were as follows:

·    To  evaluate  the  incidence  of  NHL,  stomach,  thyroid,  and  prostate  cancers  in

Watertown by smaller geographic areas within the town (i.e., CTs 3701, 3702,

3703, and 3704) to determine if areas have higher or lower cancer rates;

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·    To evaluate the incidence of the four cancer types in smaller geographic areas adjacent to the AMTL site (i.e., Brighton/Allston CTs 1.00, 2.01, 2.02, and 3.00; Cambridge CTs 3542 and 3543; Newton CT 3731);

·    To review available descriptive information reported by the Massachusetts Cancer Registry (MCR) for cancer cases in the Watertown AMTL study region related to risk factors for developing those cancers; and

·      To discuss the results of this evaluation in the context of the available scientific and  medical  literature  on  cancer  to  determine  whether  future  investigation or public health action is warranted.

IV.       METHODS FOR ANALYZING CANCER INCIDENCE DATA

A.        Case Identification

The observed number of cancer cases in this evaluation included all primary site cases  of  stomach  cancer,  prostate  cancer,  thyroid  cancer, and NHL reported to the Massachusetts Cancer Registry (MCR) diagnosed in Watertown residents and residents of adjacent census tracts between 1982-1994.  Cases were selected for inclusion based on the address reported to the hospital or reporting facility at the time of diagnosis.

The MCR, a population-based surveillance system, began collecting information on  Massachusetts  residents  diagnosed  with  cancer  in  the  state  in  1982.    All  newly diagnosed cancer cases among Massachusetts residents are required by law to be reported to the MCR within six months of the date of diagnosis (M.G.L. c.111s.111B).  Cancer incidence data were evaluated for the years 1982-1994, which was the time period for which  complete  data  were  available  at  the  time  analyses  for  this investigation were initiated.  As noted previously, the 1996 health consultation evaluated data for the time period 1982-1990 for three of the four cancer types reviewed here for Watertown and its individual  census  tracts.    These  previously  completed  analyses  are  included  here  to complement the current analysis that comprises additional years of data and census tracts

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from adjacent communities.  In addition, a review of incidence data for the years 1994-

1998 is included for the town of Watertown as a whole.

Cancer is not just one disease but describes a variety of diseases associated with abnormal cell and tissue growth.  Primary site (location in the body where the disease originated)  and  histology  (tissue  or  cell  type)  classify  the  different  cancer  types. Epidemiological  studies  have  revealed  that  different  types  of  cancer  are  individual diseases with separate causes, risk factors, characteristics and patterns of survival (Bang

1996).  Therefore, the cancer types evaluated in this report were evaluated separately.

At the request of the RAB, four cancer types were evaluated in this investigation. These include cancers of the stomach, prostate, and thyroid as well as, non-Hodgkin's lymphoma (NHL).  These cancer types were selected for evaluation based on community concerns about suspected increases in these cancers.  Only primary site cancers (i.e., cancers originating in the stomach, prostate, thyroid, or lymphatic system) were included in this evaluation. Therefore, cancers that occur as the result of the   metastases or the spread of a primary site cancer to another location in the body are not considered as a separate cancer and were, therefore, not included.

Occasionally, the MCR research file may contain duplicate reports of cases.  The data discussed in this report have been controlled for duplicate cases by excluding them from the analyses.  Duplicate cases are additional reports of the same primary site cancer case.  The decision that a case was a duplicate and should be excluded from the analyses was made by the MCR after consulting with the reporting hospital/diagnostic facility and obtaining additional information regarding the histology and/or pathology of the case. However, reports of individuals with multiple primary site cancers were included.  A multiple primary cancer case is defined by the MCR as a new cancer of the same cell type (histology) as an earlier cancer, if diagnosed in the same primary site (original location in the body) more than two months after the initial diagnosis (MCR 1996).

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B.        Calculation of Standardized Incidence Ratios (SIRs)
To  determine  whether  elevated  numbers  of  cancer  cases  have  occurred  in Watertown, its census tracts, or adjacent CTs evaluated in this report, cancer incidence data were analyzed by age-group and gender to compare the observed number of newly diagnosed cancer cases in each census tract to the number that would be expected based on the statewide cancer incidence.  Standardized incidence ratios (SIRs) were calculated for the period 1982-1994 for each of the four cancer types for the eleven census tracts and for Watertown as a whole.  SIRs were also calculated for two smaller time periods, 1982-

1986 and 1987-1994, in order to evaluate temporal trends in cancer incidence.

Because accurate age group and gender specific population data are required to calculate SIRs, the census tract is the smallest geographic area for which cancer rates can be  accurately  calculated.    Specifically,  a  census  tract  (CT)  is  a  smaller  statistical subdivision of a county.  Census tracts usually contain between 2,500 and 8,000 persons and are designed to be homogenous with respect to population characteristics (US DOC
1990). The location and boundaries of Watertown census tracts are illustrated in Figure 2. Also included in this evaluation are seven census tracts located in three towns in close proximity to the AMTL.  These include Brighton/Allston CTs 1.00, 2.01, 2.02, and 3.00; Cambridge CTs 3542 and 3543; and Newton CT 3731.  The locations of these census tracts are also shown in Figure 2.

In order to calculate incidence rates, it is necessary to obtain accurate population information.  The population figures used in this analysis were interpolated based on
1980 and 1990 U.S. census data for each census tract in the Watertown AMTL  study region  (Bureau  of  the  Census  1980,  1990).    Midpoint  population  estimates  were calculated for each time period evaluated.  To estimate the population between census years, an assumption was made that the change in population occurred at a constant rate throughout  the  ten-year  interval  between  each  census.    According  to  the  1980  U.S. census, Watertown was subdivided into four census tracts (U.S. DOC, 1980).  During the

1990 U.S. census, the Census Bureau further divided Watertown CT 3701 producing five

CTs in Watertown.  However, for the purposes of this study, in order to evaluate cancer

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incidence by census tract over time, the split tracts in 1990 (CTs 3701.01 and 3701.02)

were combined to be consistent with data from the 1980 census.

C.        Explanation/Interpretation of an SIR

An SIR is an estimate of the occurrence of cancer in a population relative to what might  be  expected  if  the  population  had  the  same  cancer  experience  as  some  larger comparison population designated as “normal” or average.  Usually, the state as a whole is  selected  to  be  the  comparison  population.    Using  the  state  of  Massachusetts  as  a comparison population provides a stable population base for the calculation of incidence rates.  Due to the instability of incidence rates based on small numbers of cases, SIRs were not calculated when fewer than five cases were observed.

Specifically, an SIR is the ratio of the observed number of cancer cases to the expected number of cases multiplied by 100.  An SIR of 100 indicates that the number of cancer cases observed in the population evaluated is equal to the number of cancer cases expected in the comparison or “normal” population.  An SIR greater than 100 indicates that more cancer cases occurred than expected and an SIR less than 100 indicates  that fewer cancer cases occurred than expected.  Accordingly, an SIR of 150 is interpreted as
50% more cases than the expected number; an SIR of 90 indicates 10% fewer cases than expected.

Caution   should   be   exercised,   however,   when   interpreting   an   SIR.      The interpretation of an SIR depends on both the size and the stability of the SIR.  Two SIRs can have the same size but not the same stability.  For example, an SIR of 150 based on four expected cases and six observed cases indicates a 50% excess in cancer, but the excess is actually only two cases.  Conversely, an SIR of 150 based on 400 expected cases and 600 observed cases represents the same 50% excess in cancer, but because the SIR is based upon a greater number of cases, the estimate is more stable.  It is very unlikely that 200 excess cases of cancer would occur by chance alone.

The reader may want to compare one census tract's SIR with another, or compare an SIR for a cancer type in Watertown with an SIR for that cancer type in another town.

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Such a comparison, however, is not appropriate or meaningful because each census tract is age-adjusted to a standard (i.e., the state cancer rate and the specific age distribution of the tract's population).  The SIR values are estimates of cancer incidence that serve as indicators of incidence after adjusting for the age distribution of a population.  Small differences in a population's age distribution can be sufficient to affect some change in SIR values.  Therefore, the comparison of SIRs in tracts with differences in their age distribution  for  the  purpose  of  stating  which  tract  has  a  higher  SIR  would  result  in misleading information and possibly incorrect conclusions.

D.        Calculation of 95% Confidence Interval
To determine if the observed number of cases is significantly different from the expected number or if the difference may be due solely to chance, a 95% confidence interval (CI) was calculated for each SIR (Rothman and Boice 1982).  A 95% CI assesses the magnitude and stability of an SIR.  Specifically, a 95% CI is the range of estimated SIR values that have a 95% probability of including the true SIR for the population.  If the  95%  CI  range  does  not  include  the  value  100,  then  the  study  population  is significantly  different  from  the  comparison  or  “normal”  population.    “Significantly different” means there is less than 5% percent chance that the observed difference is the result of random fluctuation in the number of observed cancer cases.

For example, if a confidence interval does not include 100 and the interval is above 100 (e.g., 105-130), then there is a statistically significant excess in the number of cancer cases.  Similarly, if the confidence interval does not include 100 and the interval is below 100 (e.g., 45-96), then the number of cancer cases is  statistically significantly lower than expected.  If the confidence interval range includes 100, then the true SIR may be 100, and it cannot be concluded with sufficient confidence that the observed number of cases is not the result of chance and reflects a real cancer increase or decrease.  Again, as a result of the instability of incidence rates based on small numbers of cases, statistical significance was not assessed when fewer than five cases are observed.

In addition to the range of the SIR estimates contained in the confidence interval, the width of the confidence interval also reflects the stability of the SIR estimate.  For

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example, a narrow confidence interval (e.g., 103-115) allows a fair level of certainty that the calculated SIR is close to the  true SIR for the population.  A wide interval (e.g., 85-
450) leaves considerable doubt about the true SIR, which could be much lower than or much higher than the calculated SIR.  This would indicate an unstable statistic.

E.         Determination of Geographic Distribution

The geographic distribution of cancer cases in Watertown and the adjacent CTs evaluated in this report was determined using available address information from the MCR indicating residence at the time of diagnosis.  This information was mapped for each individual using a computerized geographic information system (GIS) (MapInfo
1996).  This allowed for the assignment of census tract location for each case as well as an  evaluation  of  the  spatial  distribution  of  cases  at  a  smaller  geographic  level  (i.e., neighborhoods).  The geographic distribution was assessed using a qualitative evaluation of the point pattern of cases within the town and within each census tract evaluated.  In instances where the address information was incomplete (i.e., did not include specific streets or street numbers), efforts were made to research those cases using telephone books and town residential lists issued within two years of an individual’s diagnosis.

F.         Demographic Analysis

For  the  purposes  of  this  investigation,  demographic  trends  were  reviewed  in Watertown and the adjacent census tracts involved in the study.  Data from the U.S. Census  Bureau  was  used  to  evaluate  demographic  trends  in  age,  race,  sex,  percent educated beyond high school, median household income, and percent below poverty level
(Bureau of the Census 1990) (see Table 1).  It is important to note that even though these census tracts are located adjacent to each other, it is difficult to give a comparative analysis  of  cancer  incidence  results  between  towns  or  census  tracts  that  are  not demographically  related.    Socioeconomic  and  demographic  variables  can  affect  the outcome of cancer incidence data.  For instance, studies have consistently shown an association  of  stomach  cancer  with  low  socioeconomic  status  based on census tract information, education, family income, or occupation (reviewed in Nomura 1996).  As

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previously stated, data for Watertown and the adjacent CTs shows that these areas are not demographically similar and therefore a comparative analysis of SIRs between CTs is not appropriate.

G.        Evaluation of Cancer Risk Factors
Research has shown that there are more than 100 different types of cancer, each with different causative or risk factors.  Environmental contamination has been associated with certain types of cancer while a number of cancer types have been associated with behavioral risk factors such as tobacco use and diet.  However, cancer may also be caused by one or several factors acting over time.  Also, many cancers have a lengthy latency period (i.e., the interval between first exposure to a disease-causing agent and the appearance of symptoms of the disease [Last 1995]).  For most cancers, the latency period can range from 10 to 30 years and in some cases may be more than 40 to 50 years
(Bang 1996; Frumkin 1995).  The MCR routinely collects data related to risk factors for individuals diagnosed with cancer.  The available risk factor information from the MCR was evaluated for those cancers found to be elevated in this analysis (e.g., age,  smoking status, occupation, etc.). Information about personal risk factors (e.g., family history, hormonal events, diet, etc.) which may also influence the development of cancer is not collected by the MCR and was therefore not evaluated in this investigation.

V.        RESULTS OF CANCER INCIDENCE ANALYSIS
The following sections present cancer incidence rates for Watertown as a whole, Watertown  census  tracts,  and  the  seven  census  tracts  located  in  neighboring  cities adjacent to the site.  Figure 2 depicts the location of the census tracts studied in this investigation.    The  census  tract-specific  analyses  help  in  understanding  whether  the incidence of cancers observed town wide or region wide may be explained by an increase or decrease in cases in a particular geographic area of a particular town.

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A.        Cancer Incidence in Watertown
This section presents results of the cancer incidence analysis for Watertown as a whole  and  for  each  census  tract  evaluated.    Tables  2  through  6  summarize  cancer incidence data for Watertown for three different periods: the 13-year period 1982-1994 and the two smaller time periods, 1982-1986 and 1987-1994.  Table 2 reviews cancer incidence data townwide for the three different time periods while Tables 3 through 6 summarize cancer incidence data for Watertown CTs 3701, 3702, 3703, and 3704 for the same time periods.

1.  Cancer Incidence in Watertown as a Whole (Table 2)
During the 13-year period 1982-1994, two of the four cancer types evaluated in Watertown occurred statistically significantly  more often than expected:  NHL (98 cases observed vs. 75.8 cases expected, SIR=129, 95% CI=105-158) and prostate cancer (293 cases observed vs. 246.3 expected, SIR=119, 95% CI=106-133) (see Table 2).  NHL also occurred more often than expected among males  and among females during 1982-1994 but neither elevation was statistically significant.  When examined by the two smaller time  periods,  NHL  was  elevated  for  each  time  period  among  males  and  females combined, among males, and among females.  None of these elevations was statistically significant.

The  elevation  in  prostate  cancer  was  primarily  the  result  of  a  statistically significant elevation that occurred during the 1987-1994 time period.  During this period there was a 28% increase in prostate cancer above the statewide incidence (224 observed vs. 174.7 expected, SIR=128, 95% CI=112-146).  During the earlier time period, 1982-
1986, prostate cancer occurred about as expected based on the state rate (69 observed vs. approximately 70 expected).

During  1982-1994,  thyroid  cancer  occurred  more  often  than  expected  among males and females combined (26 cases observed vs. 19.5 expected).  This elevation was due to an elevation among females (21 cases observed vs. 14.3 expected).  Neither elevation   was   statistically   significant.      Thyroid   cancer   among   males   occurred approximately equal to expected.  When examined by smaller time periods, thyroid

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cancer occurred about as expected during 1982-1986 and was elevated during 1987-1994. Again, this elevation was due to an increase in the incidence of this cancer type among females.

Stomach cancer occurred more often than expected for both males and females in all time periods evaluated.  About one or two more cases over the expected number occurred among males for each time period while about three to five more cases occurred among females.  No elevation was statistically significant.

As noted previously, townwide cancer incidence data from the MCR for the years
1994-1998 were reviewed for Watertown as a whole (MDPH, 2001).  During these years, the incidence of prostate cancer was statistically significantly elevated with respect to the state rate in Watertown (147 cases observed vs. approximately 108 expected, SIR=136). Townwide elevations in NHL and thyroid cancer were also observed among males and females combined as well as among males and females when evaluated separately by gender, however, these elevations were not statistically significant.  Among males and females combined, 39 individuals were diagnosed with NHL where approximately 31 cases  were  expected  and  15  individuals  were  diagnosed  with  thyroid  cancer  where approximately 11 cases were expected.  Stomach cancer occurred at about the rate expected (13 cases observed vs. approximately 14 expected).

2.  Cancer Incidence in Census Tract 3701 (Table 3)
Census tract 3701 is located in the western portion of Watertown, removed from the AMTL site.  During the 13-year period 1982-1994, an elevation occurred in the incidence of NHL in CT 3701 (39 cases observed vs. approximately 31 expected).  This elevation was primarily due to an increase of approximately 7 cases above the expected number among males and females combined during the 1987-1994 time period (28 cases observed vs. 20.6 expected).  Neither elevation was statistically significant.  One more individual than expected was diagnosed with NHL during 1982-1986 (11 cases observed vs. 10 expected).

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Prostate cancer occurred more often than expected during 1982-1994 (116 cases observed  vs.  approximately  99  expected),  but  this  elevation  was  not  statistically significant.  The elevation was due to a statistically significant elevation of prostate cancer during 1987-1994 (94 cases observed vs. 71.3 expected, SIR=132, 95% CI=107-
161).  Prostate cancer occurred less often than expected during the earlier time period
1982-1986 (22 cases observed vs. approximately 27 expected).

Both stomach and thyroid cancers occurred slightly more often than expected during 1982-1994 in CT 3701.  However, these elevations represented approximately two cases above the expected number for each cancer type (22 stomach cancer cases observed vs. approximately 20 expected and 10 thyroid cancer cases observed vs. approximately 8 expected).  These slight elevations were the result of lower-than-expected rates during the earlier time period 1982-1986 and higher-than-expected rates during 1987-1994.

3.  Cancer Incidence in Census Tract 3702 (Table 4)

Census tract 3702 is located in the northern region of Watertown and, like CT
3701,  does  not  border  the  AMTL  site.    During  the  time  period  1982-1994, cancer incidence in this census tract occurred approximately at or near the expected rates for stomach and thyroid cancers.  Prostate cancer was statistically significantly elevated (94 cases observed vs. 67.3 cases expected, SIR=140, 95% CI=113-171).  The observed elevation was primarily due to the statistically significant elevation during 1987-1994 (72 cases observed vs. 47.1 cases expected, SIR=153, 95% CI=120-193).  During the earlier time period, 1982-1986, the incidence of prostate cancer was about as expected (22 cases observed vs. approximately 20 cases expected, SIR=110).

In CT 3702, NHL occurred slightly more often than expected among males and females combined during 1982-1994 (24 cases observed vs. approximately 20 expected). This elevation was due to an excess of 5 cases diagnosed among females (15 cases observed vs. 10 expected).  Neither elevation was statistically significant.  During the two smaller time periods, excesses of approximately one to three cases occurred among males and females combined, with elevations primarily due to slightly higher incidence rates

14

among females in this census tract.  Again, these elevations were the result of small increases above the expected number and were not statistically significant.

4.  Cancer Incidence in Census Tract 3703 (Table 5)

Census tract 3703 is located in the eastern section of Watertown and borders the AMTL site.  Between 1982-1994, cancer incidence was approximately at or near the expected rates among  males, females, and males and females combined for three out of the  four  cancer  types  evaluated  in  census  tract  3703.    Among  males  and  females combined during this time period, the incidence of NHL, prostate cancer, and stomach cancer  was  lower  than  expected  (14  cases  of  NHL  observed  vs.  approximately  15 expected; 47 cases of prostate cancer observed vs. approximately 49 expected; and 8 cases  of  stomach  cancer  observed  vs.  approximately  10  expected).    Although  not statistically significant, thyroid cancer occurred more often than expected in this census tract (7 cases observed vs. 3.6 expected), with approximately one excess case among males and two excess cases among females.  Similar trends were observed when results were evaluated by the two smaller time periods, 1982-1986 and 1987-1994.

5.  Cancer Incidence in Census Tract 3704 (Table 6)
Cancer incidence for the four cancer types in CT 3704, located in the southern portion of Watertown adjacent to the AMTL site, generally occurred at a greater rate than expected based on state rates (refer to Table 6).  During the 13-year time period 1982-
1994, NHL occurred approximately twice as often as expected in this census tract.  This result was statistically significant for males and females combined (21 cases observed vs.

10.6 expected, SIR= 197, 95% CI=122-302) and for males (11 cases observed vs. 5.1

cases expected, SIR=217, 95% CI=108-389).

Stomach cancer incidence was also statistically significantly elevated at about twice the expected rate for males and females combined for the time period of 1982-1994
(13 cases observed vs. 6.4 cases expected, SIR= 204, 95% CI=109-350).  However, the relatively  small  number  of  cases  observed  and  the  width  of  the  confidence  interval suggest  that,  although  statistically  significant,  this  SIR  is  somewhat  unstable.    The

15

observed  elevation  was  due  to  elevated  rates  among  both  males  and  females  when evaluated separately.  Among males, 7 cases of stomach cancer were observed versus 3.5 expected  (SIR=198).    Among  females,  6  cases  were  observed  versus  2.8  expected
(SIR=212).  However, neither elevation achieved statistical significance.

Prostate and thyroid cancers occurred more often than expected in CT 3704 (36 cases  of  prostate  cancer  observed  vs.  31.1  expected  and  5  cases  of  thyroid cancer observed vs. 3.2 expected) but the elevations observed were not statistically significantly different from the expected incidence.

Evaluation by the two smaller time periods, 1982-1986 and 1987-1994, revealed that the elevated rate for NHL among males and females combined observed for the entire 13-year time period were primarily due to a statistically significant elevation for the earlier time period 1982-1986 (9 cases observed vs. 3.7 cases expected, SIR=243). NHL was also elevated during the later time period, 1987-1994 (12 cases observed vs. 7 expected), but this elevation was not statistically significant.

When the incidence of stomach cancer was evaluated by smaller time periods, the incidence   of   stomach   cancer   was   higher   in   1982-1986   (7   cases   observed   vs. approximately 3 expected) than during the later time period 1987-1994 (6 cases observed vs. approximately 4 expected).  The elevation in prostate cancer observed during 1982-
1994 was the result of less than three additional cases over the expected number during each of the two smaller time periods.  Finally, the elevated rate of thyroid cancer in CT
3704   during   the   13-year   period   1982-1994   can   be   attributed   to   an   excess   of approximately two cases during 1987-1994.

B.        Cancer Incidence in Brighton/Allston

Tables 7 through 10 summarize the results of cancer incidence analysis for the four CTs (1.00, 2.01, 2.02, and 3.00) evaluated in Brighton/Allston, which is part of Boston.  These census tracts were chosen for evaluation at the request of the  Watertown AMTL RAB due to their proximity to the AMTL site.  They are located southeast of the Watertown CTs that border the AMTL site, across the Charles River (see Figure 2).  The

16

following sections present results for the census tracts evaluated in the  Brighton/Allston area.

1.  Cancer Incidence in Census Tract 1.00 (Table 7)

In  CT  1.00,  the  incidence  of  stomach,  prostate,  and  thyroid  cancer  occurred approximately at or near the expected rates for all three time periods examined and for both genders.  During the overall time period 1982-1994, 4 individuals were diagnosed with stomach cancer as expected, 19 individuals wee diagnosed with prostate cancer while 21 cases were expected, and one individual was diagnosed with thyroid cancer while about two cases were expected.  The incidence of NHL was about as expected for the overall period 1982-1994 and the earlier time period 1982-1986.  However, during the time period 1987-1994 there was a statistically significant elevation of NHL among males (7 cases observed vs. 2.4 cases expected, SIR=288, 95% CI=115-593) in this area of Brighton/Allston.  However, the number of cases was relatively small and the fairly wide 95% confidence interval (115-593) indicates that this SIR is somewhat unstable.  In addition, no  cases of NHL among females were reported during 1982-1994, where 3.3 cases were expected.

2.  Cancer Incidence in Census Tract 2.01(Table 8)

In census tract 2.01, cancer incidence for stomach, prostate, thyroid and NHL occurred approximately at or near the expected rates for all three time periods examined and for both genders.  During the 13-year period 1982-1994, 14 cases of prostate cancer were  observed  versus  18.9  cases  expected  (SIR=74),  however,  this  result  was  not statistically significant.  The incidence of prostate cancer was lower than expected in both smaller time periods.

3.  Cancer Incidence in Census Tract 2.02 (Table 9)

Results   for   CT   2.02   revealed   that   NHL   and   thyroid   cancer   occurred approximately at or near the expected rates for all three time periods examined and for both genders.  Although not statistically significant, stomach cancer occurred slightly more often than expected based on statewide rates during 1982-1994 (6 cases observed

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vs. 4.2 cases expected).  This was primarily due to more cases diagnosed among males in this  census  tract  (4  cases  observed  vs.  2.4  expected).    Prostate  cancer  was  slightly elevated during the 13-year period, however, this was based on less than three additional cases  above  the  expected  number  and  was  not  statistically  significant.    The  slight elevation in the number of prostate cancer cases can be attributed to an excess of less than three cases during the later time period, 1987-1994.

4.  Cancer Incidence in Census Tract 3.00 (Table 10)
NHL and stomach cancer were diagnosed approximately at or near the expected rates among males, females, and males and females combined for all three time periods evaluated  in  census  tract  3.00.    Although  not  statistically  significant,  thyroid  cancer occurred slightly more often than expected during 1982-1994 (5 cases observed vs. 3.7 cases expected).  This elevation can be attributed to a slight elevation in thyroid cancer among females in CT 3.00 (4 cases observed vs. 2.7 expected).  The incidence of prostate cancer was lower than expected (32 cases observed vs. 37.5 cases expected) in this area of Brighton/Allston, however, this result was not statistically significant.

C.        Cancer Incidence in Cambridge
Tables 11 and 12 present the results of cancer incidence analysis for CTs 3542 and  3543  in  Cambridge.    These  census  tracts  are  located  to  the  northeast,  directly adjacent to Watertown CT 3703, which borders three sides of the AMTL site (located in the southwest corner of CT 3703).  The results of the Cambridge census tract analyses are summarized below.

1.  Cancer Incidence in Census Tract 3542 (Table 11)

In CT 3542 cancer incidence for stomach, thyroid and NHL was approximately at or lower than the expected rates for all three time periods examined and for both genders. During 1982-1994, prostate cancer occurred slightly more often than expected (32 cases observed vs. 28.2 expected), due to an elevation during the earlier time period 1982-1986

(11  cases  observed  vs.  7.5  expected).    However,  neither  elevation  was  statistically

18

significant.  The incidence of prostate cancer during the later time period 1987-1994 was approximately equal to the expected rate (21 cases observed vs. 20.6 cases expected).

NHL occurred less often than expected during 1982-1994 (3 cases observed vs. 8 cases expected), but this difference was not statistically significant.  The incidence of stomach cancer was lower than expected based on statewide rates (2 cases observed vs.
5.3 cases expected).  This was primarily due to the fact that no cases of stomach cancer occurred among males in this CT during 1982-1994 while approximately 3 cases were expected.

2.  Cancer Incidence in Census Tract 3543 (Table 12)
In census tract 3543, for the time period 1982-1994, the incidence rates of all cancer types evaluated were approximately at or near the expected rates for all three time periods examined and for both genders.  The difference between the expected and the observed numbers of cases for all cancer types, all time periods, and both genders was no more than one or two cases.

D.        Cancer Incidence in Newton

Table 13 summarizes the results of cancer incidence analysis for Newton CT

3731.    This  census  tract  is  located  across  the  Charles  River,  to  the  southwest  of

Watertown CTs 3703 and 3704, the area that includes the AMTL site.

1.  Cancer Incidence in Census Tract 3731 (Table 13)

In census tract 3731 there were no statistically significant elevations of any of the four cancer types evaluated.  The incidence of stomach cancer was elevated for males and females  combined  between  1982-1994  (10  cases  observed  vs.  5.5  cases  expected, SIR=182).  However, this elevation was not statistically significant (95% CI=87-335) and was the result of small increases above the expected number of cases (i.e., three or less) during the smaller time periods 1982-1986 and 1987-1994.  NHL was also elevated for males  and  females  combined  between  1982-1994  (12  cases  observed  vs.  9.3  cases expected, SIR=130).  The slight elevation in NHL was primarily the result of an elevation

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in  this  cancer  type  among  females  during  1987-1994 (7 cases observed vs. 3 cases expected).  Neither elevation was statistically significant.

Prostate cancer occurred about as or less often than expected across all three time periods  evaluated  in  CT  3731.    Four  cases  of   thyroid  cancer  occurred  versus approximately 3 expected during 1982-1994.  This cancer type was slightly elevated during the earlier time period 1982-1986 (3 cases observed vs. approximately 1 expected) while one fewer case than expected occurred during the later time period 1987-1994.

VI.       EVALUATION OF CANCER RISK FACTOR INFORMATION

As previously mentioned, cancer is a term that describes a variety of diseases.  As such,  epidemiological  studies  have  shown  that  different  cancer  types  have  separate causes, patterns of incidence, risk factors, characteristics and trends in survival.

Available case information related to gender, race, and age was reviewed for each of the cancer types evaluated in the study region (i.e., NHL, thyroid cancer, stomach cancer, and prostate cancer) to assess whether an atypical pattern exists among cases diagnosed in the area under investigation.  In addition, smoking status and occupation were  reviewed  for  census  tracts  with  statistically  significant  elevations  of  cancer. Although the incidence of stomach cancer is associated with lower socioeconomic status
(Nomura 1996), neither social class, income, nor education level appear to be important risk  factors  for  thyroid  cancer,  prostate  cancer,  or  NHL  (Ron  1996;  and  Ross  and Schottenfeld 1996; Scherr and Mueller 1996).

Some epidemiological investigations have indicated that certain gender and ethnic groups experience increases or decreases in the incidence of a particular cancer type. Review  of  trends  in  cancer  incidence  among  racial or gender groups allows for the determination of patterns that may be indicative of risk factors for increased cancer (i.e., differences in personal habits, dietary practices, education and environmental exposures). Although  SIRs  were  not  calculated  for  different racial groups because of the small numbers of cases in non-white groups, the case distribution for the four cancer types evaluated was reviewed.

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In addition, age is a risk factor in many cancers, including NHL, thyroid cancer, stomach cancer, and prostate cancer.  As noted above, town and census tract SIRs were calculated after adjusting for the age distribution of the population.  In addition, age group-specific  SIRs  were  calculated  for  Watertown  to  evaluate  cancer  incidence  in comparison to age  group-specific rates for the state of Massachusetts as a whole.  A review of age group specific SIRs for each census tract was not possible because of the small  numbers  of  cases  in  each  group.    However,  where  there  was  a  statistically significant elevation of cancer cases in a particular census tract, the distribution of cases by age was reviewed.

Tobacco use is a risk factor in many cancers, including NHL, prostate cancer, and stomach cancer.  The smoking status of individuals in Watertown and adjacent census tracts diagnosed with these cancers during the years 1982-1994 was reviewed.

Occupational information as reported to the MCR was reviewed for those cancer types that have been associated with exposures in specific occupations.  This information was reviewed in an attempt to determine the likelihood that occupational factors may have  played  a  role  in  the  occurrence  of  cancer  in  Watertown  and  adjacent  CTs  in Brighton/Allston, Cambridge, and Newton.  It should be noted that occupational data reported  to  the  MCR  are  limited  to  job  title  and  do  not  include  specific  job  duty information that could further define exposure potential for individual cases.  Further, these data are often incomplete as cases can be reported as unknown, at home, or retired.

The following sections describe the results of the analysis of available risk factor information.

A.        Non-Hodgkin’s Lymphoma

In Massachusetts, the incidence of NHL increased by 50% from 1982 to 1997
(MCR 1997, 2000).  Gender, race, age, smoking status, and environmental exposure as well as HIV infection and other immune deficiencies are all possible risk factors for NHL.

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1.  Gender/Race Distribution
Among all NHL types combined there is a greater male to female ratio and white to black ratio (NCI 1996).  Demographic  data for Watertown show that the town is predominantly Caucasian (96%) and that females make up about 55% of the population
(see Table 1).  Watertown as a whole exhibited a statistically significant elevation in NHL incidence during the period 1982-1994.   The cases were predominantly Caucasian and  both  males  and  females  experienced  elevations  in  NHL  incidence  of  similar magnitude (approximately 30% more cases than expected).  However, the pattern of NHL incidence in individual Watertown CTs varied:  in CT 3701, the elevated incidence of NHL was of similar magnitude for both males and females; in CT 3702, the incidence of NHL was lower than expected among males while females experienced approximately
50%  more  cases  than  expected;  in  CT  3703,  the  incidence  of  NHL  was  lower  than expected among females but higher than expected among males; and in CT 3704, both males  and  females  experienced  higher  than  expected  rates  of  NHL  with  males experiencing  a  statistically  significant  elevation  (SIR=217,  95%  CI=108-389)  during

1982-1994.

All 7 cases of NHL that were observed in Brighton/Allston CT 1.00 between 1987 and 1994 occurred in Caucasian males (SIR=288, 95% CI=115-593).  Both males and females experienced NHL approximately at or near the expected rates in other census tracts in Brighton/Allston (i.e., CTs 2.01, 2.02, and 3.00).  In Cambridge CT 3542, NHL occurred approximately half as often as expected among both males and females during
1982-1994.  In Cambridge CT 3543, NHL occurred less often than expected among males and approximately at the expected rate among females.  Finally, in Newton CT
3731, males experienced NHL at a lower rate than expected while females experienced approximately 70% more cases than expected during 1982-1994, however this elevation was based on three additional cases over the expected number.  Individuals diagnosed with NHL in Watertown and adjacent census tracts in Brighton/Allston, Cambridge, and Newton were predominantly Caucasian.

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2.   Age Distribution
NHL occurs at all ages, however the incidence of this cancer generally increases with age.  In Watertown overall and in the two census tracts with statistically significant elevations in NHL (i.e., CT 3704 and Brighton/Allston CT 1.00), the incidence of this disease also displayed an increasing pattern with increasing age; 61% of Watertown cases were age 65 years or older.  Age-specific incidence rates indicate that the elevation in NHL incidence in Watertown does not appear to be the result of an elevation among any one age group.  Elevations compared to the state rate were observed in all age groups, however, the largest increases in NHL incidence in Watertown between 1982 and 1994 occurred  in  the  20-44  and  65-74  age  groups.    A  similar  pattern  was  observed  in Watertown CT 3704.

In  Brighton/Allston  CT  1.00,  all  age  groups  experienced  NHL  at  lower  than expected rates except individuals between the ages of 65 and 74 (5 cases observed vs. 1.9 expected).  The statistically significant elevation in NHL cases among males for this CT during 1987-1994 can most likely be attributed to the increase in this age group.  In general, in Brighton/Allston CTs 1.00, 2.01, 2.02, and 3.00, Cambridge CTs 3742 and
3743, and Newton CT 3731, the incidence of NHL cases was higher with increasing age, which is consistent with the age pattern for this cancer.  However, in Newton CT 3731, the incidence of NHL among individuals in the 20-44 age group was approximately two times greater than expected based on state rates (4 cases observed vs. approximately 2 expected).

3.  Smoking Status

Although a clear relationship has not been established, some studies have found a positive association with the incidence of NHL and smoking (Brown et al. 1992, Linet et al. 1992, Tatham net al. 1997).  Available information on smoking habits  was reviewed for  each  of  the  individuals  diagnosed  with  NHL  in  Watertown.    The  percentage  of individuals diagnosed with NHL who reported themselves as either a current or former smoker  at  the  time  of  their  diagnosis  was  very  similar  in  both  Watertown  and Massachusetts (see Figure 3A).  Approximately 37% of individuals diagnosed with NHL

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in Watertown and 36% in Massachusetts reported themselves as a current or former smoker.  In addition, the number of cases for which smoking status was unknown was similar for the town and the state.  Of the individuals in Watertown with known smoking status, 47% were current or former smokers.  In Brighton/Allston CTs 1.00, 2.01, 2.02, and 3.00, approximately 42% of individuals diagnosed with NHL were current or former smokers.  Smoking status was unknown in 26% of cases.  Of those with known smoking status,  approximately  57%  reported  being  current  or  former  smokers  at  the  time  of diagnosis.  In Cambridge CTs 3542 and 3543, 20% were current or former smokers. However, smoking status was unknown for half of the cases.  Of those with known smoking  status,  the  percentage  of  current  or  former  smokers  was  40%.    Finally,  in Newton CT 3731, 50% of individuals diagnosed with NHL reported themselves as either current or former smokers.  Only 2 out of the 12 cases had unknown smoking status.  Of the individuals with known smoking status, 60% were current or former smokers.

4.  Occupation
Some occupations have also been associated with an increased risk of developing NHL, specifically occupations related to chemicals or agriculture.  Farmers, herbicide and  pesticide  applicators,  and  grain  workers  appear  to  have  the  most  increased  risk

(Tatham et al. 1997; Zahm 1990, 1993).

Review  of  available  occupational  information  for  each  of  the  NHL  cases  in

Watertown revealed that 36% of the 98 cases had a reported occupation as "retired,”
“housewife,” or "at home.”  Occupation was unknown for an additional 15% of cases. The occupational data for the remaining cases did not indicate any jobs associated with an increased risk of NHL, with the possible exception of three individuals who were hairdressers.  Analysis of occupational data for NHL cases in census tracts adjacent to Watertown  (i.e., Brighton/Allston CTs 1.00, 2.01, 2.02, and 3.00; Cambridge CTs 3542 and  3543;  and  Newton  CT  3731)  also  did  not  reveal  any  jobs  associated  with  an increased risk of this disease.  However, as noted above, MCR data are limited to job title only and does not include specific information related to job duties.  Therefore, it could

24

not be determined if occupation may have played a role in the development of NHL

among these individuals.

B.        Prostate Cancer

Cancer  of  the  prostate  is  the  most  common  cancer  among  American  men, accounting for approximately 31% of all male cancer cases.  An estimated 198,100 new cases occur per year in the U.S. and African American men are at least 50% more likely to develop prostate cancer than men of any other racial and ethnic group (ACS 2001).  In addition to race, age is a major risk factor for prostate cancer.  Other possible risk factors include  tobacco  use,  a  diet  high  in  fat,  and  occupational  exposures  (e.g.,  exposures associated with rubber companies).

1.  Gender/Race Distribution
Prostate cancer was statistically significantly elevated for Watertown as a whole in the time periods of 1982-1994 and 1987-1994.  The MCR also reported that prostate cancer was statistically significantly elevated for Watertown as a whole during 1994-
1998.    Analysis  of  case  data  for  the  1982-1994  period  showed that the cases were predominantly Caucasian.  The racial breakdown of individuals in Watertown diagnosed with  prostate  cancer  is  as  follows:  95%  Caucasian,  1%  African  American,  and  4% unknown.  The large percentage of Caucasian individuals with prostate cancer is most likely attributed to the fact that 96% of the male population in Watertown is Caucasian. The racial distribution of individuals with prostate cancer was similar in adjacent census tracts in Brighton/Allston, Cambridge, and Newton.  In Brighton/Allston CTs 1.00, 2.01,
2.02, and 3.00, 92% of individuals with prostate cancer were Caucasian, two individuals were African American, two were Chinese, one was Hispanic, and two were of unknown race.  In Cambridge, one individual with prostate cancer was African American, two were of unknown race, and the remainder were Caucasian.  In Newton CT 3731, all 26 individuals with prostate cancer were Caucasian.

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2.  Age Distribution
Prostate cancer incidence increases with age and is primarily a disease among men in older age groups (i.e., above 65 years) (ACS 1996; NCI 1996).  In fact, more than 70% of all prostate cancers are diagnosed in men over age 65 (ACS 2001).  Watertown and adjacent census tracts experienced a similar age pattern among individuals diagnosed with prostate cancer.  Overall, 293 reported cases of prostate cancer were diagnosed in Watertown men during 1982-1994, and 245 of these (84%) were over the age of 65.  Similar trends were observed in smaller geographic areas within Watertown (i.e., CTs 3701 and 3702).  The statistically significant elevations in prostate cancer incidence in CTs 3701 and 3702 during the period 1987-1994 cannot be attributed to an increase among individuals in any one age group as elevations were observed among age groups 45-64, 65-74, 75-84, and 85+ for both census tracts.

3.  Smoking Status
Epidemiologic studies analyzing a possible association between cigarette smoking and prostate cancer are not conclusive, although some show a positive relationship (Ross and Schottenfeld 1996).  Approximately 43% of Watertown residents diagnosed with prostate cancer during 1982-1994 were current or former smokers, which is comparable to the percentage of individuals with prostate cancer in the state (40%) (see Figure 3B). Of the individuals in Watertown with known smoking status, 55% were current or former smokers at the time of diagnosis.  In the Brighton/Allston census tracts evaluated in this report, approximately 52% of individuals with prostate cancer were current or former smokers.  The percentage of individuals with prostate cancer in Brighton/Allston census tracts who were smokers was approximately 12% higher than in the state as a whole (see Figure  3C).    Smoking  status  was  unknown  for  24%  of  the  cases.    In  this  area, approximately 68% of individuals with known smoking status were current or former smokers.  In Cambridge CTs 3542 and 3543, 41% of individuals with prostate cancer reported themselves as current or former smokers.  Smoking status was unknown for 30% of cases.  Of those with known smoking status, 58% were current or former smokers. Finally, in Newton CT 3731, 46% of cases were diagnosed among current or former smokers.    Smoking  status  was  unknown  for  27%  of  cases.    Approximately  63%  of

26

individuals with known smoking status reported being a current or former smoker at the time of diagnosis.

4.  Occupation

An increased risk of prostate cancer has been consistently reported for employees of rubber companies, but no specific exposure related to the increase has been identified
(Schottenfeld and Ross 1996).  Other occupations that may be related to an increased risk of developing prostate cancer include welding, electroplating, and alkaline battery production. Exposure to cadmium as a result of working in these occupations has been suggested to be associated  with  the  increase  in  prostate  cancer  among  these  workers,  however,  several subsequent studies have been unable to confirm this possible association.  Further, it is thought that if occupation is associated with  this cancer type, it is likely responsible for a very small proportion of all prostate cancer cases (Ross and Schottenfeld 1996).  Review of occupational data for prostate cancer cases in Watertown and adjacent census tracts did not indicate many jobs that may be related to an increased risk of this disease.  Out of a total of
469 individuals diagnosed with prostate cancer in this area, five individuals worked for a tire company, five were electrical workers, and three were welders (approximately 3% of all cases).  However, as previously discussed, occupational data from MCR are often limited and  40%  of  individuals  were  reported  to  the  MCR  with  “unknown”  or  “retired”  as occupations.  Therefore, it could not be determined with certainty whether occupation may have played a role in the development of prostate cancer among these individuals.

C.        Stomach Cancer

An estimated 21,700 new cases of stomach cancer will be diagnosed in the U.S. in
2001 and approximately 12,800 individuals will die of the disease (ACS 2001).  Specific risk factors for this cancer include gender, race, and age.  A diet high in nitrates and pre- existing medical conditions such as gastric ulcers and chronic gastritis are associated with the development of stomach cancer.  Tobacco use and certain occupational exposures are also possible risk factors.

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1.  Gender/Race Distribution
Stomach cancer is twice as common among men as women, and incidence tends to be higher among Hispanics, African Americans, and Asian Americans (Nomura 1996). With the exception of Watertown CT 3704, the incidence of stomach cancer occurred approximately at or near the expected rates in Watertown and surrounding census tracts in Brighton/Allston, Cambridge, and Newton.  In Watertown CT 3704, the incidence of stomach cancer was approximately twice the expected rate (13 cases observed vs. 6.4 expected,  SIR=204),  a  statistically  significant  result.    With  the  exception  of  one individual for whom race was unknown, all of the individuals diagnosed with stomach cancer in CT 3704 were Caucasian.

The incidence of stomach cancer exhibited no specific pattern with regard to gender   in   census   tracts   in   Brighton/Allston,   Cambridge,   and   Newton.      In Brighton/Allston CTs 1.00 and 2.01, stomach cancer occurred more often than expected for  males  and  less  often  than  expected  for  females.    In  Brighton/Allston  CT  2.02, stomach cancer occurred about as often as expected for females and more often than expected for males while in CT 3.00, the incidence was approximately at the expected rate for males but higher than expected for females.  In Cambridge CTs 3542 and 3543, stomach cancer occurred less often than expected for both males and females.  Finally, in Newton CT 3731, the incidence of stomach cancer was higher than expected for both genders but females experienced more than twice the number of cases expected based on state rates.  With the exception of one individual for whom race was unknown and one individual with reported race as “other,” all individuals diagnosed with stomach cancer in Watertown  were  Caucasian.    In  Brighton/Allston,  two  individuals  diagnosed  with stomach cancer were Chinese, one was Hispanic, one was unknown, and the remainder of the individuals were Caucasian.  In Cambridge and Newton, the majority of individuals with stomach cancer were Caucasian.  Although stomach cancer is twice as common among Hispanics, African Americans, and Asian Americans, the racial distribution of individuals  with  this  cancer  type  in  Watertown  and  the  adjacent  census  tracts  in Brighton/Allston,  Cambridge,  and  Newton  reflects  the  relatively  large  Caucasian population in these areas.

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2.   Age Distribution
The incidence of stomach cancer increases with age and rises sharply after the age of 60 (Nomura 1996).  Although stomach cancer incidence was generally higher for older age groups in Watertown and adjacent census tracts, no specific pattern of disease with regard to age emerged upon analysis of cases.  In Watertown CT 3704, a statistically significant  elevation  was  observed  in  stomach  cancer  overall.    The  increase  in  the incidence of stomach cancer in this CT cannot be attributed to an increase in any one age group, as all age groups experienced elevations.  In Watertown as a whole, 38 of the 56 cases were 65 years or older (68%) and in CT 3704, 10 of the 13 cases were 65 years or older (77%), which is consistent with the age pattern observed in the general population.

3.  Smoking Status
The  association  between  stomach  cancer  and  cigarette  smoking  is  unclear. However,  several  studies  have  found  that  heavy  smokers  have  an  increased  risk  of developing stomach cancer, especially smokers who routinely swallow cigarette smoke

(Nomura 1996).  Furthermore, both mainstream and sidestream tobacco smoke contains

N-nitroso compounds, suspected carcinogens in the development of stomach cancer.

In  Watertown,  48%  of  individuals  diagnosed  with  stomach  cancer  reported themselves as current or former smokers.  This compares to about 44% of stomach cancer cases in Massachusetts.  Smoking status was unknown for 27% and 23% of  individuals diagnosed  with  stomach  cancer  in  Watertown  and  Massachusetts,  respectively  (see Figure 3D).  In Watertown, of those individuals diagnosed with stomach cancer whose smoking status was known, 66% reported being current or former smokers at the time of diagnosis.    In  the  Brighton/Allston  census  tracts  evaluated,  approximately  46%  of individuals diagnosed with stomach cancer were current or former smokers at the time of their diagnosis.  Smoking status was unknown for 29% of individuals.  Of those with known smoking status, 65% were current or former smokers.  In Cambridge CTs 3542 and 3543, smoking status was known for all 7 cases and 29% were current or former smokers.  In Newton CT 3731, 30% of individuals reported themselves as current or

29

former smokers.  Smoking status was unknown for 20% of individuals.  Of those with known smoking status, 38% were current or former smokers at the time of diagnosis.

4.  Occupation

Available evidence indicates that occupational exposures do not play a major role in the incidence of stomach cancer.  It is suspected that coal miners and asbestos workers are  at  increased  risk  for  developing  stomach  cancer,  however,  this  evidence  is inconclusive.    Other  occupations  possibly  associated  with  stomach  cancer  include workers  in  the  chemical,  rubber,  oil  refinery,  metal-products  industries,  and  other industries  involving  mineral  dust  exposure.    Suspected  carcinogenic  agents  include asbestos,  polycyclic  aromatic  hydrocarbons,  and  N-nitroso  compounds  (reviewed  in Nomura  1996).    Occupational  data  on  97  individual  cases  of  stomach  cancer  in Watertown and adjacent census tracts in Brighton/Allston, Cambridge, and Newton was reviewed.  Although the analysis did not indicate any jobs that might be associated with an increased risk  of stomach cancer, except for one individual in Brighton/Allston and one  individual  in  Watertown,  much  of  the  occupational  data  were  incomplete.    For approximately half the cases, occupation was listed as “retired,” “housewife,” “at home,” or “unknown.”  Therefore, it could not be determined with certainty if occupation may have played a role in the incidence of stomach cancer in this community.

D.        Thyroid Cancer

The thyroid is one of the least cancer-prone organs in the body, representing only

0.54% cancers occurring among men in the U.S. and 1.7% among U.S. females (Ron
1996).  It is, however, one of the most common neoplasms in adolescents and young adults.  Thyroid cancer is primarily associated with external x-ray treatments of benign medical conditions in childhood or external radiation (e.g., from atomic bomb fallout exposures).  Gender, race, and age also play roles in the development of this disease.

1.  Gender/Race Distribution
The female to male ratio of thyroid cancer is high after puberty and during the reproductive years, then declines at the time of menopause.  Thus it is of note that the

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thyroid gland becomes enlarged during puberty and pregnancy and may change in size and activity during the menstrual cycle (Robbins et al. 1984).  In addition, the incidence of thyroid cancer is about two times greater among whites than among blacks and persons of Asian origin have elevated rates compared to persons of other ethnic backgrounds living in the same areas (Ron 1996).

The incidence of thyroid cancer   in Watertown and adjacent census tracts is consistent with the reported pattern of this disease.  In general, more cases of thyroid cancer occurred among females than among males across all areas evaluated.  Again, the majority of individuals diagnosed with thyroid cancer in these areas were Caucasian.

2.  Age Distribution

Although  the  incidence  of  thyroid  cancer  increases  with  increasing  age,  it  is comparatively  slower  than  most  other  cancer  types  and  is  a  cancer  predominantly diagnosed among individuals between the ages of 15 and 39.  In this age group, thyroid cancer accounts for 8.7% of all newly diagnosed cancers, as compared to 0.7% between the ages of 55 and 64, and 0.3% at age 80 and above.  In fact, thyroid cancer was ranked as one of the five most frequent cancers among persons aged 15-39 (Ron 1996).

In  Watertown,  54%  of  the  diagnosed  cases  were  between  the  ages  of  15-39. Review of age group specific SIRs revealed that the highest rates of thyroid cancer for Watertown and surrounding areas during 1982-1994 occurred in the 0-19 and 20-44 age groups as expected based on available evidence regarding the age pattern of this disease.

3.  Smoking Status/Occupation
Smoking has not been shown to be a risk factor in the development of thyroid cancer  (ACS   1999).    Further,  the  available  literature  indicates  that  occupational exposures also do not play a major role in the incidence of thyroid cancer (Ron 1996).

VII.     Evaluation of Geographic Distribution
Place of residence at the time of diagnosis was geocoded and mapped for each of the four cancer types to assess any possible geographic pattern of cases.  In addition to

31

quantitatively determining census tract-specific incidence ratios for each cancer type, a qualitative  evaluation  was  conducted  to  determine  whether any specific cancer type appeared to be concentrated in some area(s) within Watertown or adjacent census tracts. Figure 2 depicts the locations of these census tracts within their respective towns and in relation to the AMTL site.

A.        Watertown
Review of data for NHL for Watertown showed that the distribution of cases throughout individual and adjacent census tracts does not present any specific geographic pattern.  In general, the geographic pattern of cancer cases in Watertown during 1982-
1994 showed a distribution of cases that is consistent with the population density of the town.  However, there appeared to be a small concentration of NHL cases in Watertown CT  3703  (not  near  the  AMTL  site)  and  stomach  cancer  cases  in  CT  3704  in  a neighborhood  bordering the AMTL site.  For confidentiality reasons, MDPH cannot reveal the exact location of these cases.

As  noted  earlier,  in  January  2000,  MDPH  released  a  report  on  a  follow-up evaluation of risk factor information and residential histories for certain cancer types that appeared  concentrated  in  Watertown  based  on  findings  from  the  original  health consultation (ATSDR 1996, 2000).  Included in this investigation were four individuals diagnosed with NHL in CT 3703 and four individuals diagnosed with stomach cancer in CT 3704 whose residences at the time of diagnosis (between 1982 and 1990) were located near one another.  Based on residential histories, available risk factor information
(e.g., age, smoking status, occupation), and known environmental risk factors associated with these cancers, MDPH concluded that the occurrence of NHL and stomach cancer among these groups of individuals did not suggest any single factor (environmental or non-environmental)  that  might  explain  the  distribution  of  cancer  in  these  areas  of Watertown.

The apparent concentrations of NHL and stomach cancer found upon review of individuals diagnosed between 1982 and 1994 represent the same areas identified in the

1996 health consultation, with one additional individual diagnosed with cancer in each

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group.  Residential histories were conducted for each of these ten individuals using town residential lists (Town of Watertown, 1964-1994).  Review of this information revealed that of the five individuals diagnosed with NHL who lived near each other in CT 3703, four  had  lived  at  their  address  for  greater  than  or  equal  to  20  years  at  the  time  of diagnosis and one had lived at their address for at least three years prior to diagnosis.  Of the five individuals diagnosed with stomach cancer in CT 3704, three had lived at their address for greater than or equal to 20 years at the time of diagnosis, two had lived at their address for at least 12 years, and one had lived at their address at least 11 years prior to diagnosis.  Based on available risk factor information for these individuals, it does not appear  that  these  individuals  share  a  single  common  risk  factor  (environmental  or otherwise) other than place of residence.

B.        Brighton/Allston, Cambridge, and Newton
Review of the geographic distribution for the four cancer types evaluated revealed no apparent spatial patterns for any specific cancer type in Brighton/Allston CTs 1.00,
2.01, 2.02, and 3.00.  Although a statistically significant elevation in the incidence of NHL among males was observed in  CT 1.00 during the later time period 1987-1994 (7 cases observed vs. 2.4), the geographic distribution of cases did not appear concentrated in any one area of this census tract.

Review of the geographic distribution for the four cancer types evaluated revealed no apparent spatial patterns for any specific cancer type in Cambridge CTs 3742 and

3743 or Newton CT 3731.

VIII.    COMMUNITY ENVIRONMENTAL CONCERNS

As noted above, this analysis was prompted by a request from the Watertown AMTL  RAB  based  on  community  concerns  about  the  possibility  of  a  relationship between cancer incidence and environmental exposures at a National Priority List (NPL) site in Watertown (e.g., AMTL).  In 1997, as required by law for all sites on the EPA National Priorities List, ATSDR released a public health assessment for the AMTL site

(ATSDR 1997).  The public health assessment evaluated whether chemical contaminants

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disposed or released into the environment at AMTL and other former Watertown Arsenal properties have the potential to cause adverse health effects.  Three exposure pathways were  identified  in  the  public  health  assessment:  subsurface  soil  contamination,  fish contamination in the Charles River, and past air releases of depleted uranium.  In the case of subsurface soil contamination, ATSDR concluded that the general public is not likely to be exposed to or come into contact with residual contamination at the site.  ATSDR noted that results of fish sampling prompted the MDPH to issue a fish consumption advisory for this area of the Charles River due to high levels of PCBs in carp.  If this advisory is followed, exposure to contaminants in fish from the Charles River poses no apparent public health hazard.  Finally, depleted uranium was burned at the Watertown Arsenal in the past.   However, ATSDR concluded that possible exposure to airborne contaminants  was  below  levels  of  health  concern  for  the  few  residents  living  close enough to the Arsenal to have been exposed in the past.  ATSDR also noted that future land use of the AMTL site poses no public health hazard because before the land can be transferred for reuse, all necessary cleanup actions must be completed.

Although contaminants were found in groundwater and subsurface soils at the AMTL site, ATSDR concluded that it is unlikely   that residents could be exposed to significant concentrations of contaminants that would have the potential to produce adverse health effects in areas surrounding the former Arsenal site.  ATSDR calculated cancer  risk  estimates  related  to  radiation  dose  for  individuals  possibly  exposed  to airborne depleted uranium and found that the lifetime cancer risk was approximately 10 times less than the risk of cancer expected from background radiation levels (e.g., natural radiation  in  the  environment).    In  addition,  ATSDR  noted  that  lung  cancer  would comprise  virtually  all  the  risk  from  this  potential  exposure.    In  an  initial  health consultation for Watertown, review of lung cancer incidence in Watertown or its census tracts did not indicate elevations in this cancer type or geographic patterns that would suggest a relationship to the AMTL site (ATSDR 1996).  Further, the most recent data available from the MCR for the time period 1994-1998 show that lung cancer incidence in Watertown as a whole was lower than expected (MDPH 2001).

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IX.       DISCUSSION
In   the   majority   of   the   eleven   census   tracts   evaluated   in   Watertown, Brighton/Allston, Cambridge, and Newton, NHL, prostate cancer, stomach cancer, and thyroid cancer occurred approximately at or near the expected rates based  on statewide incidence during 1982-1994.  Some statistically significant elevations, however, were noted.  Statistically significant elevations were noted for NHL in Watertown as a whole and in CT 3704, as well as for Brighton/Allston CT 1.00 (for males only) during one or more time periods.  Watertown as a whole and CTs 3701 and 3702 displayed statistically significant elevations of prostate cancer in one or more time periods evaluated.  Stomach cancer was statistically significantly elevated in Watertown  CT 3704 during the overall time period 1982-1994.  While some other elevations were noted in the incidence of these cancer types in certain census tracts, these were primarily based on small numbers of cases  and  were  not  statistically  significant.    Analysis  of  the  statistically  significant elevations generally revealed no consistent trends of cancer incidence at the census tract level or in relation to the AMTL site throughout the 13-year time period evaluated.  In addition, the census tracts with statistically significant elevations in cancer incidence were generally not adjacent to each other.

Analysis  of  more  recent  data  (e.g.,  for  the  years  1994-1998)  revealed  that incidence rates for prostate cancer have remained statistically significantly elevated in Watertown as whole.  Elevations were also noted for NHL and thyroid cancer, however, these elevations were not statistically significant.

The evaluation of the geographic distribution of the four cancer types for the years 1982-1994 revealed that two areas identified in the 1996 consultation still appeared to have some concentration of cases (i.e., NHL in CT 3703 and stomach cancer in CT
3704).    No  other  area  in  all  census  tracts  evaluated  appeared  to  have  any  unusual concentration of cases within the census tract.  MDPH further evaluated the NHL and stomach  cancer  cases  that  appeared  concentrated.    Results  indicated  that  based  on residential histories and known risk factor information, it does not appear that any single cause, environmental or otherwise, is likely to explain the occurrence of all of these cases.  In addition, based on the information reviewed in this analysis related to risk

35

factors for development of these cancers (e.g., age, gender, smoking, and occupation), this analysis did not reveal any pattern or trend that was unexpected or inconsistent with established incidence patterns for these cancer types.  It is likely that smoking played a role in the incidence of NHL, prostate cancer, and stomach cancer in Watertown and surrounding  communities.    However,  due  to  the  number  of  individuals  for  whom smoking status was unknown, the extent of this role is not clear.  Therefore, it appears unlikely that a single factor, including environmental factors, was primarily responsible for the observed pattern of cancer incidence in the Watertown area.  As discussed below, a number of factors or combination of factors which were not able to be evaluated in this report may influence the development of the cancer types evaluated in this investigation.

A.        Non-Hodgkin’s Lymphoma

Overall, between 1973 and 1997, the incidence of NHL in the U.S. grew 81%
(Garber 2001).  This increase has been attributed to better diagnosis, greater exposure to causative  agents,  and,  to  a  lesser  extent,  the  increasing  incidence  of  AIDS-related lymphomas  (Devesa  and  Fears  1992;  Scherr  and  Mueller  1996).    Although  primary factors  related  to  the  development  of  NHL  include  conditions  that  relate  to  the suppression of the immune system, viral infections, and certain occupational exposures, these factors are thought to account for only a portion of the increase observed in this cancer type (Scherr and Mueller 1996).

NHL  is  more  common  among  people  who  have  abnormal  or  compromised immune systems, such as those with inherited diseases that suppress the immune system, organ  transplant  recipients,  and  individuals  with  autoimmune  disorders  (Scherr  and Mueller 1996).  NHL has also been reported to occur more frequently among individuals with conditions that require medical treatment resulting in suppression of the immune system, such as cancer chemotherapy.  However, current evidence suggests that the development of NHL is related to suppression of the individual's immune system as a result of treatment rather than the treatment itself (Scherr and Mueller 1996).

Several viruses have been shown to play a role in the development of NHL. Among  organ  transplant  recipients,  suppression  of  the  immune  system  required  for

36

acceptance of the transplant leads to a loss of control or the reactivation of viruses  that have  been  dormant  in  the  body  (e.g.,  Epstein-Barr  Virus  [EBV]  and  herpesvirus infections).  In addition, because cancer-causing viruses are known to cause lymphomas in various animals, it has been proposed that these types of viruses may also be associated with the development of NHL among humans without compromised immune systems. Infection with the human T-cell leukemia/lymphoma virus (HTLV-I) is known to cause T-cell lymphoma among adults.  However, this is a relatively rare infection and most likely contributes only a small amount to the total incidence of NHL (Scherr and Mueller, 1996).  EBV infection is common among the general population and has been shown to play a role in the development of most cases of transplant and AIDS related NHL.  The combination of immune system deficiencies and EBV infection may cause some people to develop NHL (ACS, 1998).  Although viruses are causal factors for some subtypes of NHL, to date, studies have shown that the role of EBV in the development of NHL in the general population may not be large (Scherr and Mueller, 1996).  Moreover, the high prevalence of EBV in the general population suggests that EBV may be only one of several factors in the development of this cancer.

As noted above, herbicides and insecticides have been linked to an increased risk for NHL among agricultural workers.  Recent studies have suggested that contamination of drinking water with nitrate may be associated with an increased risk of NHL (Ward et al. 1996).  Nitrate forms N-nitroso compounds, which are known carcinogens and can be found in tobacco, smoked or salt-dried fish, bacon, sausages, other cured meats, beer, pickled vegetables, and mushrooms.

Although NHL is associated with a number of risk factors, the causes of this disease remain unknown.  Further, most patients with NHL do not have any known risk factors (ACS 1998).

Based on the data evaluated, a statistically significant elevation in the incidence NHL was observed for the town of Watertown as a whole for 1982-1994 (SIR=129) and in CT 3704 (SIR=197), adjacent to the AMTL site.  Census tracts 3701 and 3702 also displayed elevated but not statistically significant rates of NHL.  Therefore, the significant

37

elevation in CT 3704 alone does not appear to explain the increased incidence of NHL in the town of Watertown.  In CT 3703, which surrounds most of the AMTL site, the incidence rate of NHL was as expected.  During 1994-1998, NHL for Watertown as a whole was still elevated but no longer statistically significantly elevated.  In regards to the potential risk of NHL when exposed to nitrates in drinking water, it should be noted that groundwater at the AMTL site was not found to be contaminated with nitrates.  Further, exposure by the general public to contaminated groundwater is not likely because the water in this area is not used for domestic purposes (ATSDR 1997).  The municipal drinking water within 4 miles of the site is supplied by surface water sources located to the west of AMTL and is unaffected by the site (EPA 2001).  The municipal drinking water is routinely tested for contaminants, including nitrate.  Nitrate levels in the Watertown drinking water supply have consistently been below EPA’s Maximum Contaminant Levels (MWRA 2001).  Some studies have suggested that environmental (i.e., chemical) exposures may be related to the development of NHL, however, no definitive association has been established.

In Brighton/Allston CT 1.00, located across the Charles River from the AMTL

site, a statistically significant increase in NHL among males was observed during the
1987-1994  time  period.    However,  review  of  information  on  residence  at  diagnosis revealed that cases were widely scattered with the census tract.  There were no NHL cases observed among females in Brighton/Allston CT 1.00 for any of the time periods evaluated.  Incidence of NHL was approximately at or near expected rates for all other census tracts evaluated in Watertown, Brighton/Allston, Cambridge, and Newton.

B.        Prostate Cancer
Prostate cancer rates are greater in countries where the population consumes more animal fat (Devesa et al. 1995; NCI 1996; Schottenfeld and Ross 1996).  Prostate growth depends on the hormone testosterone and some studies have suggested that a diet high in animal fats also increases the levels of this hormone, which may elevate the risk for prostate  cancer.    In  several  large  cohort  and  case-control  studies,  overweight  men

(defined as >30% above ideal body weight) had approximately 2.5 to 4.4 times the risk of

38

developing prostate cancer than men who  were near their desirable weight (Schottenfeld and Ross 1996).

Additional risk factors for prostate cancer include a higher prevalence of past venereal disease, as shown in several large epidemiological studies (Schottenfeld and Ross 1996).  Available epidemiological data strongly support a familial tendency toward prostate cancer occurrence.

Increasing  prostate  cancer  incidence  appears  related  to  changes  in  diagnostic methods, such as serum testing for prostate-specific antigen PSA, which has led to increased detection at earlier stages (ACS 1996; Devesa et al. 1995; NCI 1996).  By the late 1980s, prostate  cancer  became  the  most  commonly  diagnosed  malignancy  among  U.S.  men

(Devesa et al. 1995).

Prostate cancer was statistically significantly elevated among males in the town of

Watertown, particularly during the later portion of the 13 years evaluated (i.e., 1987-

1994).    Prostate  cancer  remained  statistically  significantly  elevated  townwide  during
1994-1998.  The townwide elevation from 1982-1994 was largely  a result of statistically significant elevations that occurred among males in CT 3701 during the 1987-1994 time period and CT 3702 during the 1982-1994 time period.  These census tracts are located in the northwest area of Watertown and are not near the AMTL site.  The incidence of prostate cancer was approximately at or near expected rates for all other census tracts evaluated  in  Watertown,  Brighton/Allston,  Cambridge,  and  Newton.    Review  of demographic information for prostate cancer cases revealed that 81% of cases were over the age of 65, a pattern consistent with the available literature on the disease.  In addition, review of the annual distribution of prostate cancer diagnoses in Watertown suggests that the observed elevation in incidence could be attributed to an increase in the number of individuals diagnosed with this cancer type in the early 1990s.  The incidence of prostate cancer increased sharply over time in Massachusetts from 1982 to 1992.  The same pattern  was  seen  nationally  and  is  primarily  attributed  to  increased  use  of  the  PSA screening test in the late 1980s and early 1990s (MDPH 2000).  The pattern of prostate cancer incidence in Watertown follows this trend and may be related to an increase in

39

screening and early detection of this cancer.  Analysis of the geographic distribution of prostate cancer cases and the fact that environmental risk factors are not associated with prostate cancer suggests that it is unlikely that the increased incidence of prostate cancer observed in Watertown is related to the AMTL site.

C.        Stomach Cancer

The  rate  of  stomach  cancer  incidence  is  higher  among  persons  in  lower socioeconomic classes and for those who live in colder climates (ACS 1996; Nomura
1996).  In the United States, studies have shown high rates  of this cancer in urban areas of the northeast (Nomura 1996).

The   relationship   between   diet   and   stomach   cancer   has   been   extensively researched.  A series of studies has linked the intake of nitrates and related compounds to stomach cancer (NCI 1996; Nomura 1996).  Sources of dietary nitrate include drinking water, green vegetables, cured meats, some cheeses, and other foods.  Nitrate forms N- nitroso compounds, which are potent carcinogens and can be found in smoked or salt- dried fish, bacon, sausages, other cured meats, beer, pickled vegetables, and mushrooms.

Several medical conditions are also associated with a higher risk of developing stomach  cancer  including  gastric  ulcers,  gastric  polyps,  chronic  gastritis,  intestinal metaplasia, and gastroenterostomy  (Nomura 1996).  Infection with Helicobacter pylori, believed to be a common cause of gastritis and peptic ulcers, plays a role in the initiation of precancerous stomach changes (NCI 1996).  Pernicious anemia also changes the stomach lining and may be related to increased risk for stomach cancer (NCI 1996). Radiation may also increase the risk of stomach cancer as seen in atomic bomb survivors and studies of patients treated with  X-rays for a spinal disorder (NCI 1996; Nomura

1996).  In addition, family studies have suggested a possible genetic susceptibility (NCI

1996; Nomura 1996).

With the exception of a statistically significant elevation in CT 3704 (SIR=204) and a non-significant elevation in Newton CT 3731, the incidence of stomach cancer was approximately at or near the expected rates in the town of Watertown and adjacent census

40

tracts  in  Brighton/Allston,  Cambridge,  and  Newton.  Although recent evidence links nitrates  to  stomach  cancer,  nitrates  were  not  found  in  groundwater  at  the  AMTL  site. Further, the groundwater at the site is not used for domestic purposes.  The municipal drinking water is routinely tested for contaminants, including nitrate.  Nitrate levels in the Watertown  drinking  water  supply  have  consistently  been  below  EPA’s  Maximum Contaminant Levels (MWRA 2001).  Because there are no established environmental risk factors for stomach cancer, it is not likely that the observed increases in the incidence of stomach cancer in Watertown or Newton CT 3731 are related to contamination at the AMTL site.

D.        Thyroid Cancer

Thyroid cancer is primarily associated with external (e.g., head and neck) x-ray treatments of benign medical conditions in childhood (ACS 1996; Amdur et al. 1991; BEIR 1990; EPA 1989).  Whole-body external radiation such as gamma radiation, as in the case of atomic bomb survivors, has been associated with the development of this cancer (BEIR 1988; Lundell et al. 1994; Ron et al. 1995).  An analysis of data from the Marshall Islands on radioactive fallout exposures has also shown  an association between radiation exposures and elevated thyroid cancer incidence (BEIR 1990).  Therapeutic use of radioactive iodine (primarily for treatment of thyrotoxicosis) does not appear to be associated with an increase in thyroid cancer risk (ACS 1996; BEIR 1990; Higginson et al. 1992).  Additional risk factors for thyroid cancer are non-malignant thyroid disorders and a positive family history of these disorders (Higginson et al. 1992).

Thyroid cancer occurred approximately at or near the expected rates in the town of Watertown and adjacent census tracts in Brighton/Allston, Cambridge, and Newton. Although not statistically significant, thyroid cancer occurred about twice as often as expected in Watertown CT 3703 (7 cases observed vs. 3.6 cases expected), which borders the AMTL site.  The development of thyroid cancer has been associated with exposure to radiation as a result of radioactive fallout from nuclear weapons or power plant accidents. However, the type of radiation associated with depleted uranium (alpha emitter) has not been linked to thyroid cancer.  In addition, ATSDR concluded that radiation at the AMTL

41

site from the burning of depleted uranium was below levels of health concern and that radiation dose estimates that could have resulted if exposure had occurred to Watertown residents in the past showed a lifetime cancer risk less than expected from naturally occurring radiation.  No other environmental factors have been shown to be positively associated with the development of thyroid   cancer.  Therefore, it is unlikely that the elevated incidence of thyroid cancer in CT 3703 is associated with contamination at the AMTL site.

X.        CONCLUSIONS

This analysis is descriptive in nature and can only provide an evaluation of cancer incidence in Watertown and adjacent census tracts in comparison to cancer incidence in the state.  Cancers in general have a variety of associated risk factors that are likely related to the etiology (development) of disease.  Many cancers are believed to be related largely to lifestyle factors such as cigarette smoking, diet, and alcohol consumption.  Epidemiologic studies  of  humans  and  laboratory  animals  have  related  several  cancers  to  chemical exposures in the workplace or in an individual’s environment.  Other factors associated with cancer are socioeconomic status, heredity/genetics, age, race, and geography.

Watertown  experienced  statistically  significant  elevations  in  NHL  and  prostate cancer during 1982-1994.  Review of 1994-1998 data shoed that prostate cancer remained statistically significantly elevated townwide and that NHL was elevated but no longer statistically significant.  In CT 3703, which surrounds most of the AMTL, there were no statistically significant elevations for the four cancer types evaluated.  In this census tract, NHL, prostate cancer, and stomach cancer occurred below the expected rate, while thyroid cancer occurred more often than expected (about three or four excess cases).  In CT 3704, NHL and stomach cancer were statistically significantly  elevated during one or more time periods evaluated.  However, review of the geographic distribution and available risk factor and residential history (for stomach cancer only) information did not suggest that any single factor, environmental or otherwise,  likely played a primary role in the occurrence of these cases.  Incidence rates for prostate and thyroid cancers were slightly elevated but these

42

elevations were not statistically significant and there were no geographic concentrations of cases within the census tract.

In general, for all four cancer types evaluated in Watertown and surrounding areas, the ages at diagnosis and risk factor information were consistent with what the medical literature has described regarding the occurrence of these diseases and risk factors in the general population and did not appear to be atypical.  Therefore, the pattern of cancer incidence for these four cancer types as well as other information evaluated in this report
(e.g., geographic distribution) suggests that it is unlikely that contaminants at the AMTL site played a primary role in the observed pattern of these cancer types in Watertown and surrounding areas.  However, it is beyond the scope of this investigation to determine any causal relationship or synergistic roles that risk factors discussed in this report may have played  in  the  development  of  cancer  for  individuals  in  the  Watertown  AMTL  study region.

XI.       RECOMMENDATIONS
MDPH  recommends  that  the  Watertown  Board  of  Health  consider  additional efforts to educate residents about risk factors related to the development of these cancers, particularly  prostate  and  stomach  cancers.    Special  emphasis  should  be  placed  on behavioral risk factors, such as cigarette smoking, diet, and exercise.  The BEHA will forward the results of this evaluation to the MDPH Bureau of Family and Community Health (BFCH) for consideration of future cancer control activities in Watertown.

Through the use of the Massachusetts Cancer Registry, MDPH will continue to monitor the incidence of NHL, prostate cancer, stomach cancer, and thyroid cancer in Watertown.

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XII.     REFERENCES

Agency for Toxic Substances and Disease Registry. Health consultation: residential history follow-up: Materials Technology Laboratory, Watertown, Middlesex County, Massachusetts. Atlanta: U.S. Department of Health and Human Services; 2000 Jan 3.

Agency for Toxic Substances and Disease Registry. Public health assessment for U.S. Army Materials Technology Laboratory, Watertown, Middlesex County, Massachusetts. Atlanta: U.S. Department of Health and Human Services; 1997.

American Cancer Society. 2001. Cancer Facts & Figures 2001.  Atlanta: American
Cancer Society, Inc.

American Cancer Society. 1998. Non-Hodgkin’s Lymphoma: Prevention and Risk Factors [web site]. Non-Hodgkin’s Lymphoma Resource Center, American Cancer Society. Available at: www.cancer.org/cancerinfo.

American Cancer Society. 1999. Thyroid Cancer: Prevention and Risk Factors [web site]. Thyroid Cancer Resource Center, American Cancer Society. Available at: www.cancer.org/cancerinfo.

American Cancer Society. 1996. Cancer Manual. 9th ed. Boston: American Cancer
Society, Massachusetts Division.

Amdur MO, Doull J, Klassen CD, editors. 1991. Casarett and Doull's toxicology: the basic science of poisons. 4th ed. New York: Pergamon Press.

Bang KM. 1996. Epidemiolgy of occupational cancer. Occupational Medicine 11(3):
467-485.

BEIR. 1988. Health Risks of Radon and Other Internally Deposited Alpha-Emitters. BEIR IV. Washington, D.C.: Committee on the Biological Effects of Ionizing Radiation, National Research Council.

BEIR. 1990. Health Effects of Exposure to Low Levels of Ionizing Radiation. BEIR V. Washington, D.C.: Committee on the Biological Effects of Ionizing Radiation, National Research Council.

Boring CC, Squires TS, Tong T, Montgomery S. 1994. Cancer statistics, 1994. CA Cancer J Clin 44(1):7-26.

Brown  LM,  Everett  GD,  Gibson  R,  et  al.  1992.  Smoking  and  risk  of  non-Hodgkin’s lymphoma and multiple myeloma.  Cancer Causes Control 3(1):49-55.

44

Bureau of the Census. 1990 census population: general population characteristics, Massachusetts.  U.S. Department of Commerce.

Bureau of the Census. 1980 census population: general population characteristics, Massachusetts.  U.S. Department of Commerce.

Devesa SS, Blot WJ, Stone BJ, et al. 1995. Recent cancer trends in the United States.  J Natl Cancer Inst 87(3):175-182.

Devesa SS, Fears T. 1992. Non-Hodgkin’s lymphoma time trends: United States and international data. Cancer Res 52(19 Suppl.):5432s-5440s.

Frumkin H. 1995. Carcinogens. In: Levy BS, Wegman DH, editors.  Occupational health.
3rd ed.  Boston: Little Brown and Company.

Garber K. 2001. Lymphoma rate rise continues to baffle researchers. J Natl Cancer Inst
93(7):494-6.

Higginson J, Muir CS, Munoz N. 1992. Human cancer: epidemiology and environmental causes. Cambridge Monographs on Cancer Research.  Cambridge, Great Britain: Cambridge University Press.

Last JM. 1995. A Dictionary of Epidemiology.  International Epidemiological
Association, Inc. New York: Oxford University Press.

Linet MS, McLaughlin JK, Hsing AW, et al. 1992. Is cigarette smoking a risk factor for non-Hodgkin’s lymphoma or multiple myeloma? Results from the Lutheran Brotherhood cohort study. Leuk Res 16(6-7):621-624.

Lundell  M,  Hakulinen  T,  Holm  LE.  1994.  Thyroid  cancer  after  radiotherapy  for  skin hemangioma in infancy.  Radiat Res 140(3):334-339.

MapInfo, Professional version 4.1.  1996.  Copyright MapInfo Corporation, 1985-1996. Troy, New York.

Massachusetts Cancer Registry. 2000. Cancer Incidence and Mortality in Massachusetts
1993-1997: Statewide Report. March 2000. Massachusetts Department of Public Health, Bureau of Health Statistics, Research and Evaluation, Massachusetts Cancer Registry. Boston, MA.

Massachusetts Cancer Registry. 1997. Cancer Incidence and Mortality in Massachusetts
1987-1994: Statewide Report. August 1997. Massachusetts Department of Public Health, Bureau of Health Statistics, Research and Evaluation, Massachusetts Cancer Registry. Boston, MA.

45

Massachusetts Department of Public Health. 2001. Cancer Incidence in Massachusetts
1994-1998: City and Town Supplement. Massachusetts Department of Public Health, Bureau of Health Statistics, Research and Evaluation, Massachusetts Cancer Registry. November, 2001.

Massachusetts Department of Public Health. 2000. Selected Cancers in Massachusetts Men 1982-1992. Massachusetts Department of Public Health, Bureau of Health Statistics, Research and Evaluation, Massachusetts Cancer Registry. 2000.

Massachusetts Department of Public Health. 1997. Cancer Incidence in Massachusetts
1987-1994: City and Town Supplement. Massachusetts Department of Public Health, Bureau of Health Statistics, Research and Evaluation, Massachusetts Cancer Registry. November, 1997.

Massachusetts Department of Public Health. 1996. Health consultation: Materials Technology Laboratory (U.S. Army), Watertown, Middlesex County, Massachusetts. Atlanta: U.S. Department of Health and Human Services, Agency for Toxic Substances and Disease Registry; 1996 March.

Massachusetts Water Resources Authority and Watertown Water Department. 2001. What you should know about your tap water. MWRA.

Miller BA, Riles LAG, Hankey BF, et al. 1993. SEER cancer statistics review: 1973-
1990. Bethesda: National Cancer Institute. NIH Pub. NO.  93-2789.

National Cancer Institute. 1996. Cancer rates and risks. 4th ed.  National Cancer Institute. NIH Publication No. 96-691.

Nomura A. 1996. Stomach cancer. In: Schottenfeld D, Fraumeni JF, editors. Cancer epidemiology and prevention. 2nd ed. New York: Oxford University Press.

Robbins SL, Cotram RS, Kumar V. 1984. Pathologic basis of disease. Thyroid gland. Philadelphia: WB Saunders. p. 1201-1225.

Ron E. 1996. Thyroid cancer. In: Schottenfeld D, Fraumeni JF, editors. Cancer epidemiology and prevention. 2nd ed. New York: Oxford University Press.

Ron E, Lubin JH, Shore RE, et al. 1995. Thyroid cancer after exposure to external radiation: a pooled analysis of seven studies. Radiat Res 141(3):259-277.

Ross R, Schottenfeld JF. 1996. Prostate cancer. In: Schottenfeld D, Fraumeni JF, editors. Cancer epidemiology and prevention. 2nd ed. New York: Oxford University Press.

Rothman K, Boice J. 1982. Epidemiologic analysis with a programmable calculator. Boston: Epidemiology Resources, Inc.

46

Scherr P,  Mueller N. 1996. Non-Hodgkin's lymphomas. In: Schottenfeld D, Fraumeni JF, editors. Cancer epidemiology and prevention. 2nd ed. New York: Oxford University Press.

Schottenfeld D, Fraumeni JF. 1996. Cancer epidemiology and prevention. 2nd ed. New
York: Oxford University Press.

Spitz MR, Sider JG, Katz RL, Pollack ES, Newell GR. 1988. Ethnic patterns of thyroid cancer incidence in the United States, 1973-1981. Int J Cancer 42:549-553.

Tatham L, Tolbert P, Kjeldsberg C. 1997. Occupational risk factors for subgroups of non- Hodgkin’s lymphoma. Epidemiology 8(5):1551-8.

U.S. Environmental Protection Agency. EPA New England National Priorities List
(NPL) Fact Sheet: Materials Technology Laboratory (USARMY). March 26, 2001.

U.S.   Environmental   Protection   Agency.   1989.   Risk   Assessments   Methodology, Environmental Impact Statement, NESHAPS for Radionuclides: Background Information Document,   Volume   1.   Washington,   D.C.:   Office   of   Radiation   Programs,   U.S. Environmental Protection Agency. EPA/5201/1-89-005.

Ward MH, Mark SD, Cantor KP, et al. 1996. Drinking water nitrate and the risk of non- Hodgkin’s lymphoma.  Epidemiology 7(6):465-71.

Weston RF. 1993. Phase 2: Remedial Investigation Report: Army Materials Technology
Laboratory. Contract Number DAAA 15-90-D-0009.

Zahm  SH,  Weisenburger  DD,  Babbit  PA,  et  al.  1990.  A  case-control  study  of  non- Hodgkin’s  lymphoma  and  the  herbicide  2,4-dichlorophenoxyacetic  acid  (2,4-D)  in Eastern Nebraska.  Epidemiology 1(5):349-56.

Zahm SH, Weisenburger DD, Saal RC, et al. 1993. The role of agricultural pesticide use in the development of non-Hodgkin’s lymphoma in women. Archives of Environmental Health 48(5):353-8.

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