Trends in Incidence of Early-Onset Colorectal Cancer in the United States Among Those Approaching Screening Age

Key Points Question What is the increase in the colorectal cancer incidence rate from 49 to 50 years of age when large segments of the population begin average-risk screening? Findings This cross-sectional analysis of colorectal cancer incidence rates in 1-year age increments (30-60 years) from 2000 to 2015 in the Surveillance, Epidemiology, and End Results 18 registries found an incidence rate increase of 46.1% from 49 to 50 years of age. A total of 92.9% of the cases of colorectal cancer diagnosed at 50 years of age were invasive (beyond in situ stage). Meaning Steep incidence increases from 49 to 50 years of age are consistent with preexisting colorectal cancers diagnosed via screening uptake, supporting the presence of a large undetected preclinical case burden in patients younger than 50 years that is not reflected in observed Surveillance, Epidemiology, and End Results incidence rates.