Trends in early-onset colorectal cancer incidence (2000–2022) among Black Americans and Sub-Saharan African populations.

Abstract

e15692 Background: Early-onset (age < 50) colorectal cancer (CRC) incidence is rising in low- and middle-income countries even as rates plateau in high-income countries. Black Americans have among the highest early-onset CRC rates in the U.S., whereas historically sub-Saharan Africa (SSA) has had very low rates. We compared 2000–2022 CRC incidence trends in these two populations with shared ancestry to isolate environmental and healthcare system influences from genetic predisposition. Methods: Annual age-standardized CRC incidence rates (per 100,000; ages 15–49) for U.S. Black Americans (2000–2022) were obtained from SEER. Corresponding incidence data for SSA were derived from Global Burden of Disease. Five-year CRC prevalence in SSA was also assessed to gauge survivor trends. Annual percent change (APC) was used to evaluate temporal trends. Results: Among U.S. Black Americans, early-onset CRC incidence increased by ~40% from 2000 to 2022 (10.9→15.2 per 100,000), with APC ≈1.5% per year. In SSA, incidence roughly doubled over the same period (~2.5→4.0 per 100,000), though rates there remain about 3–5-fold lower than in U.S. Blacks. Within SSA, all four subregions experienced upward incidence trends. Central SSA showed the steepest increase, from 1.9 per 100,000 in 2000 to 4.2 in 2022 (APC 3.7%). Eastern SSA had the highest early-onset CRC rate by 2022, climbing from 3.5 to 5.1 per 100,000 (APC 1.8%). Incidence in Southern and Western SSA rose more moderately, reaching 3.5 and 3.0 per 100,000 respectively by 2022 (APCs 1.7% and 2.0%). Moreover, the 5-year CRC prevalence in SSA almost doubled (from ~10 to ~17 per 100,000), indicating an increase in young CRC survivors. Conclusions: Early-onset CRC has risen in both Black Americans and SSA. However, the substantially higher rates in U.S. Blacks – despite shared ancestry – highlight predominantly environmental/lifestyle factors (e.g., Westernized diet, obesity) and differences in detection rather than genetic causes. The recent rise in SSA likely stems from Westernization and improved cancer detection in the absence of widespread screening. These findings underscore the need for interventions targeting modifiable risk factors and improved surveillance to curb early-onset CRC in SSA. Additionally, the disproportionately high early-onset CRC burden among U.S. Black Americans warrants earlier screening, targeted lifestyle interventions, and greater awareness to reduce this disparity.