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National Cancer Institute


This section defines two central survivorship-related terms, in addition to several key statistical terms. For other cancer terms, see the NCI Dictionary of Cancer Terms.

Survivorship Definitions

Cancer Survivor

An individual is considered a cancer survivor from the time of diagnosis, through the balance of his or her life. Family members, friends, and caregivers are also impacted by the survivorship experience and are therefore included in this definition.
Adapted from the National Coalition for Cancer Survivorship

Cancer Survivorship Research

Cancer survivorship research encompasses the physical, psychosocial, and economic sequelae of cancer diagnosis and its treatment among both pediatric and adult survivors of cancer. It also includes within its domain, issues related to health care delivery, access, and follow up care, as they relate to survivors. Survivorship research focuses on the health and life of a person with a history of cancer beyond the acute diagnosis and treatment phase. It seeks to both prevent and control adverse cancer diagnosis and treatment-related outcomes such as late effects of treatment, second cancers, and poor quality of life, to provide a knowledge base regarding optimal follow-up care and surveillance of cancers, and to optimize health after cancer treatment.

Statistics Definitions

Cancer Incidence

The cancer incidence rate is the number of new cancers of a specific site/type occurring in a specified population during a year, usually expressed as the number of cancers per 100,000 population at risk.1

Cancer Prevalence

Cancer prevalence is the number of people alive on a certain date who have been diagnosed with cancer. This includes individuals who are newly diagnosed, in active treatment, have completed active treatment, and those living with progressive symptoms of their disease. Prevalence is derived from long-term incidence and survival rates.1

Complete Prevalence

Represents the proportion of people alive on a certain day who previously had a diagnosis of the disease, regardless of how long ago the diagnosis was, or if the patient is still under treatment or is "cured."

Limited Duration Prevalence

Represents the proportion of people alive on a certain day who had a diagnosis of the disease within the past x years (e.g. x = 5, 10, 20 or 25 years).

Observed Survival Rate

The observed survival rate, which is obtained using standard life table procedures, represents the proportion of cancer patients surviving for a specified length of time after diagnosis.1


1 Howlader N, Noone AM, Krapcho M, Garshell J, Miller D, Altekruse SF, Kosary CL, Yu M, Ruhl J, Tatalovich Z,Mariotto A, Lewis DR, Chen HS, Feuer EJ, Cronin KA (eds). SEER Cancer Statistics Review, 1975-2011, National Cancer Institute. Bethesda, MD,, based on November 2013 SEER data submission, posted to the SEER web site, April 2014.