Speaking of Studies

Absolute risk: The risk of developing a disease over a specific period of time.

Complete response: Disappearance of all signs of cancer as a result of treatment; does not always equate to a cure.

Disease-free survival: Length of time after treatment during which no evidence of cancer is found.

Five-year survival: The percentage of patients in a population who have survived at least five years. Five years is the standard for most cancers when discussing survival.

Mean: The average of a group of numbers.

Median: The middle number(s) in a group.

Partial response: Tumor shrinkage by at least 30 percent.

Progression: Spreading or growing disease (by at least 20 percent), with or without treatment.

Progression-free survival: The length of time a patient has survived without growth of the cancer.

Relative risk: The risk of disease in an affected (exposed) group compared with a control (unexposed) group.

Stable disease: The cancer is neither growing nor shrinking.

Adapted with permission of the American Cancer Society.