Study: Appendix cancer incidence has quadrupled in older Millennials

edited by Sadie Harley, reviewed by Robert Egan

In a study estimating the incidence rates of appendiceal adenocarcinoma (AA), or appendix cancer, across birth cohorts in the United States, researchers observed a sharp increase in AA incidence rates for those born after 1945, particularly for Generation X and Millennials. These patterns suggest a timely need for etiologic research and increased AA awareness among physicians and the public.

The study is published in Annals of Internal Medicine.

Researchers from Vanderbilt University Medical Center and colleagues used the National Cancer Institute SEER (Surveillance, Epidemiology, and End Results) Program to estimate age‐specific incidence rates of AA per 100,000 persons in five‐year time periods between 1975 and 2019.

The researchers created 21 overlapping birth cohorts and estimated the incidence rates relative to a 1945 birth cohort. The researchers identified a total of 4,858 persons aged 20 years or older who were diagnosed with a pathologically confirmed primary AA (nonmucinous, mucinous, goblet cell, or signet ring cell carcinoma).

They found that age‐specific AA rates increased by time period, and incidence rates of AA more than tripled among the 1980 birth cohort and quadrupled among the 1985 birth cohort.

This pattern was reflected across all AA histologic subtypes, however, the magnitude varied. The increase in AA incidence rates was especially large among Generation X and Millennials. Because incidence rates in younger generations are often indicative of future disease burden, the findings suggest the need for histology‐specific investigations of AA as well as more awareness of rare AAs among physicians and the public.

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