LAUSR

BACKGROUND The rate of change in the incidence of colorectal cancer (CRC) among persons younger than 50 years in the United States appears to vary by demographics, tumor location, and geography. This study analyzed data from all 50 states to examine recent changes in the incidence of CRC among persons younger than 50 years and to identify key subgroups with disproportionate risk. METHODS Annual incidence rates for CRC, colon cancer, and rectal cancer in persons aged 20 to 49 years were extracted from the US Cancer Statistics for the period 2001-2017. Secular trends were examined overall and by age group, sex, race/ethnicity, stage, and state. Joinpoint regression was used to compute annual percent changes and average annual percent changes (AAPCs) as well as corresponding 95% confidence intervals (95% CIs). RESULTS The incidence of CRC increased by 1.27% (95% CI, 0.95%-1.60%) annually from 2001 to 2012 and by 3.00% (95% CI, 2.06%-3.95%) annually from 2012 to 2017. AAPCs for the period 2001-2017 were higher among persons aged 20 to 24 years (AAPC, 6.62%; 95% CI, 3.86%-9.45%) in comparison with other age groups and higher among non-Hispanic Whites (AAPC, 2.38%; 95% CI, 1.98%-2.79%) in comparison with other racial/ethnic groups. In 2001-2002, only 1 state had an age-standardized incidence rate > 13.0 per 100,000, but this number increased to 32 states by 2016-2017. CONCLUSIONS CRC rates among US adults aged 20 to 49 years increased from 2001 to 2017, with the fastest increases observed from 2012 to 2017. Increases were observed among the youngest age groups, among non-Hispanic Whites, and in states in the West, Midwest, and Rocky Mountain regions. Increasing rates across all tumor stages suggest a real increase in CRC incidence.