Commonly used cancer-related terms

Definitions to some of the most commonly used terms related to cancer.
Age-adjusted rate Some communities have a much larger proportion of older people than others. Since the risk of developing or dying from cancer is higher for older persons, a community with a large proportion of older people is likely to have more cancer cases and more cancer deaths than a community with a younger population. Age-adjustment is a way to compare cancer cases or deaths in communities with different age distributions. Age-adjusted rates are calculated by weighting the age-specific rates for a given year by the age distribution of a standard population. The weighted age-specific rates are then added to produce the adjusted rate for all ages combined.
Age-specific rate

The rate among people of a particular age range in a given time period. Age-specific rates are calculated by dividing the number of people in an age group who have a particular condition by the number of people in that same age group overall.


Showing no signs of cancer.


The removal of cells, fluid, and/or tissue for microscopic examination.


The treatment of cancer with chemicals or drugs that are designed to stop cancer cells from growing.


The cancer has spread to parts of the body far away from the original point where it began.

In situ

The earliest stage of cancer, before the cancer has spread, when it is limited to a small number of cells and has not invaded the organ itself.


The number of people who are newly diagnosed with a disease/condition/illness during a particular time period.


A cancer that has spread beyond the layer of cells where it started into the tissue around it, and has the potential to spread to other parts of the body.

Lifetime Risk

The likelihood of developing a disease/condition/illness sometime in your life.


Cancer found only in the body part (organ) where it began; it hasn't spread to any other parts.




A cancer that has spread from the site where it started to other parts of the body, such as to the bone or the liver.


The number of people who die of a disease/condition/illness during a particular time period.

Origin or primary site

The organ or part of the body where a cancer starts.


A reduction in the chance of developing a disease.


The cancer has spread beyond the original point where it started to the nearest surrounding parts of the body (other tissues).

Relative Survival Rate

The percentage of people that have not died from a particular disease within a certain time period.

Risk factor

Anything that raises a person's chance of getting a disease.


Tests that are given to check for early signs of disease in people who have no symptoms. Screening can identify potential disease very early when treatment is most effective.


How far along a cancer has developed in a person's body.

Survival Rate

The percentage of people diagnosed with a disease who are still alive a certain time later. The figure most often given is for 5-year survival.


An indication of a disease/condition/illness.


Medicines or procedures that a health care provider can use to treat a disease.

Tumor A lump, mass, or swelling caused by the multiplication of cells. A tumor can be either benign (non-cancerous) or malignant (cancerous).

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