Compare Cohort and Period Trends across Cancer Sites


When searching for clues as to what sorts of factors are driving cancer rates, it is often useful to examine whether the rates differ more by year of birth (i.e. birth cohort) or calendar year (i.e. period). For some cancers this is fairly obvious. For example:

  • Smoking rates differ by birth cohort, and so do lung cancer rates
  • The rapid introduction of the PSA screening test in the late 1980’s and early 1990’s dramatically drove up prostate cancer incidence rates in that period,

while for other cancers the cause of change in rates is less obvious. For example:

  • There has been a steady rise in the incidence of esophageal adenocarcinoma but the cause(s) are largely unknown.

The purpose of this website is to produce a series of graphs for a wide range of cancers that depict the contribution of birth cohort and period factors to changes in rates. The SEER 9 registries provide the data for incidence rates, and death certificates are collected by every state and collated by the National Center for Health Statistics to provide cause-specific mortality rates for the entire US. Rates derived for single years of age and single calendar years are smoothed in order to more easily see the shape of the trends (see Methodology: Smoothing).

On this website you can:

This website is not intended to substitute for detailed analyses of cancer trends using sophisticated Age-Period-Cohort (APC) statistical methodologies, but rather to provide a broad overview of the types of factors driving trends for a wide range of cancers, and to provide a foundation for more detailed analyses of individual cancer sites.

Suggested Citation

  • Article: Holford TR, Chen HS, Annett D, Krapcho M, Dorogaeva A, Feuer EJ. CP*Trends: An Online Tool for Comparing Cohort and Period Trends Across Cancer Sites. American Journal of Epidemiology 2019 Jul 7;188(1):1361–1370. [View Article]External Website Policy
  • Website: CP*Trends: An Online Tool to Compare Cohort and Period Trends across Cancer Sites. Surveillance Research Program Web Site. https://surveillance.cancer.gov/cptrends/. National Cancer Institute. Published 2019. Accessed [month, day, year].