Trends in locoregional colorectal cancer incidence by race and ethnicity in US adults aged 45-49 with updated screening guidelines (2013-2022).

44 Background: Colorectal cancer (CRC) screening guidelines from the American Cancer Society recommended lowering the starting age from 50 to 45 in 2018. We examined the impact of this guideline on locoregional CRC incidence overall and across racial and ethnic groups. Methods: We used the US Cancer Statistics public use database to identify locoregional cases diagnosed between 2013-2022 in adults aged 45-49. We calculated delay- and age-adjusted annual incidence rates (IRs) per 100,000 persons, overall and by race and ethnicity. We used NCI’s Joinpoint Regression Program Version 5.4.0 to estimate annual percent change (APC) and 95% confidence intervals. We measured IRs for the 5-year periods before and after 2018 and calculated incidence rate ratios (IRR) to evaluate the potential impact of the screening guideline change. IRs and IRRs were calculated using SEER*Stat Version 9.0.41. Results: We identified 75,007 cases. The APC for overall incidence was 1.34% (95% CI 0.23-2.25) from 2013-2020 and significantly increased to 18.12% (95% CI 13.33-21.47) from 2020-2022. The sharp rise in APC was observed across all groups, with the largest absolute increase seen among non-Hispanic (NH) Asian or Pacific Islander (API) persons (28.32% increase, Table). From 2013-2017, compared to NH White persons, the IR for NH Black persons (IRR 1.08) was higher while the IRs for NH API (IRR 0.76) and Hispanic (IRR 0.71) persons were lower. There was no significant IR difference between NH White and NH American Indian/Alaskan Native (AI/AN) persons. From 2018-2022, compared to NH White persons, the IR for NH AI/AN persons (IRR 1.26) became higher while the IRs for NH API (IRR 0.81) and Hispanic (IRR 0.75) persons remained lower. Rates for NH Black persons were no longer different. Conclusions: After updated CRC screening guidelines, incidence of locoregional CRC significantly increased across all racial and ethnic groups for adults aged 45-49. IRR trends compared to NH White persons suggest relative screening uptake has decreased for NH Black persons but stayed stable or increased for other groups. Trends in locoregional CRC incidence by race and ethnicity in US adults aged 45-49, 2013-2022. Group 2013-2020 APC (95% CI) 2020-2022 APC (95% CI) 2013-2017 IR (95% CI) 2013-2017 IRR vs NH White (95% CI) 2018-2022 IR (95% CI) 2018-2022 IRR vs NH White (95% CI) NH White 1.76 (-2.32-3.40) 16.57 (6.00- 23.06) 24.2 (23.8-24.6) 28.5 (28.1-28.9) NH Black -0.16 (-2.60- 1.21) 20.77 (11.53-26.54) 26.1 (25.2-26.9) 1.08 (1.04-1.12) 29.4 (28.5-30.3) 1.03 (0.99-1.07) NH AI/AN 4.03 (-12.02-20.72) 21.88 (3.59-41.29) 25.4 (22.1-29.1) 1.05 (0.91-1.20) 35.9 (31.8-40.3) 1.26 (1.11-1.42) NH API 0.99 (-8.29- 4.47) 29.31 (10.52-42.48) 18.5 (17.4-19.5) 0.76 (0.72-0.81) 22.9 (21.9-24.0) 0.81 (0.77-0.85) Hispanic 2.28 (-0.14- 3.69) 17.29 (9.51- 22.39) 17.2 (16.6-17.9) 0.71 (0.68-0.74) 21.4 (20.8-22.1) 0.75 (0.73-0.78)