Cancer prevalence is the number (or percent) of people in a population who are alive on a given date and who previously were diagnosed with cancer. Cancer prevalence is an important estimate of the cancer burden and cancer survivorship in a population.
In the past, cancer prevalence was estimated from the Connecticut tumor registry incidence data. Beginning in 2001, a new methodology was developed using all SEER data to produce cancer prevalence estimates that are more representative of the Nation. Limited duration prevalence (the proportion of people alive at a given date who were diagnosed with cancer during a selected number of years) is estimated using the counting method, which takes into account loss to followup. Estimates of complete prevalence, the proportion of people alive with a history of cancer, are calculated using a statistical method that estimates the proportion of people alive who were diagnosed with cancer before the start of SEER registration.
The cancer prevalence methodology is being disseminated to researchers through the 2003 release of SEER*Stat, which includes the software to calculate limited duration prevalence estimates and its variance. The software is a powerful tool that will enable researchers to calculate prevalence in very flexible ways; for example, for different cancer sites, stages, races, time prior to diagnosis, and different methods for the inclusion of people with multiple tumors.
Further methods are being developed to estimate prevalence of long survivors from childhood cancers.
Mariotto A, Gigli A, Capocaccia R, Tavilla A, Clegg LX, Depry M, Scoppa S, Ries LAG, Rowland JH, Tesauro G, Feuer EJ. Complete and limited duration cancer prevalence estimates. SEER Cancer Statistics Review, 1973-1999 2002;19. http://seer.cancer.gov/csr/1973_1999/
Ries LAG, Eisner MP, Kosary CL, Hankey BF, Miller BA, Clegg L, Mariotto A, Fay MP, Feuer EJ, Edwards BK (eds). SEER Cancer Statistics Review, 1975-2000, National Cancer Institute. Bethesda, MD. http://seer.cancer.gov/csr/1975_2000/.