SEER database analysis of incidence of appendiceal adenocarcinoma in birth cohorts across the United States

Incidence rates of appendiceal adenocarcinoma (AA) are increasing across all age groups in the USA. Birth cohort patterns of AA can provide new, etiologic clues. A retrospective cohort study using the SEER program included 4858 persons aged 20 year or older when diagnosed with AA from 1975 tot 2019. Five-year age groups and time periods were used. Incidence rates of AA more than tripled among the 1980 birth cohort (IRR 3.41; 95% CI 2.54-4.56) and more than quadrupled among the 1985 birth cohort (4.62; 3.12-6.82) compared with the 1945 birth cohort. Age-specific incidence rates of AA increased across successive birth cohorts after 1945 for all tumor histologic types. The authors conclude that there are strong birth cohort effects for AA.