Shifts in the Proportion of Distant Stage Early-Onset Colorectal Adenocarcinoma in the United States

Carcinoids, frequently classified as "colorectal cancer" contribute to rising early-onset colorectal cancer (EOCRC) incidence rates (IR) and have distinct staging distributions compared to often advanced stage adenocarcinomas (screening target). Thus, assessing temporal shifts in early-onset distant stage adenocarcinoma can impact public health.2000-2016 Surveillance Epidemiology and End Results (SEER) 18 yearly adenocarcinoma IRs were stratified by stage (in situ, localized, regional, distant), age (20-29, 30-39, 40-49, 50-54-year-olds), subsite (colorectal, rectal-only, colon-only), and race [non-Hispanic whites, non-Hispanic Blacks (NHB), Hispanics] in 103,975 patients. Three-year average annual IR changes (pooled 2000-2002 IRs compared with 2014-2016) and cancer stage proportions (percent contribution of each cancer stage) were calculated.Comparing 2000-2002 with 2014-2016, the steepest percent increases are in distant stage cancers. Colon-only, distant adenocarcinoma increased most in 30-39-year-olds (49%, 0.75/100,000→1.12/100,00, P < 0.05). Rectal-only, distant stage increases were steepest in 20-29-year-olds (133%, 0.06/100,000→0.14/100,000, P < 0.05), followed by 30-39-year-olds (97%, 0.39/100,000→0.77/100,000, P < 0.05) and 40-49-year-olds (48%, 1.38/100,000→2.04/100,000, P < 0.05). Distant stage proportions (2000-2002 to 2014-2016) increased for colon-only and rectal-only subsites in young patients with the largest increases for rectal-only in 20-29-year-olds (18%→31%) and 30-39-year-olds (20%→29%). By race, distant stage proportion increases were largest for rectal-only in 20-29-year-old NHBs (0%→46%) and Hispanics (28%→41%). Distant colon proportion increased most in 20-29-year-old NHBs (20%→34%).Youngest patients show greatest burdens of distant colorectal adenocarcinoma. Although affecting all races, burdens are higher in NHB and Hispanic subgroups, although case counts remain relatively low.Optimizing earlier screening initiatives and risk-stratifying younger patients by symptoms and family history are critical to counteract rising distant stage disease.