Abstract We assessed the differences in overall survival (OS) by age at colorectal cancer (CRC) diagnosis among African Americans (AA) in Metropolitan Detroit. These data were collected as a part of the Detroit Research on Cancer Survivors (ROCS) and the Disparities and Cancer Epidemiology (DANCE) studies. We analyzed data from 491 AA participants newly diagnosed with invasive CRC from 2013 to 2021 within the Metropolitan Detroit Cancer Surveillance System catchment area. Participants (n = 491) completed written, online, or interviewer-assisted surveys and were categorized as early onset (EO: 50 years, n = 64) and average onset (AO: ≥ 50 years, n = 427) based on age at CRC diagnosis. Demographic, clinical, pathological, dietary, physical activity, smoking and alcohol variables at time of enrollment were assessed among the two subgroups. Kaplan-Meier survival analysis was performed to produce crude and site- and stage-stratified survival curves. Cox proportional hazards models were used to model survival outcomes among early versus average onset AA CRC participants adjusting for insurance type, primary site, and SEER stage (local, regional, distant). The average age of onset was 43. 6 (range 28 – 49) and 63. 7 (range 50 - 84) for EO and AO cases respectively. EO cases were more likely to be diagnosed at distant stages (25. 4% vs 15. 6%, p0. 02) and less likely to be diagnosed with a right-sided tumor (35. 9% vs 46. 8%, p0. 05) although this did not reach statistical significance. EO cases were also more likely to have private insurance (46. 9% vs 23. 2%, p0. 0001) and report never smoking (73. 4% vs 49. 4%, p0. 002). EO CRC cases had higher mortality overall (HR = 1. 32, 95% CI 0. 82 – 2. 12). While no mortality differences were detected by age for local stage CRC, mortality was higher for EO cancers for both regional (HR = 1. 99, 95% CI 1. 28 – 3. 08) and distant (HR = 10. 18, 95% CI 6. 50 – 15. 93) stage CRC after adjustment for site and insurance. Within-stage differences in mortality between EO and AO cases may be indicating more aggressive disease or differences in treatment in AA EO compared to AO CRC patients. Our ongoing analyses address tumor phenotypes and other factors that may be associated with more aggressive disease. Citation Format: Grace J. Lee, Siddhi Patil, Kristen S. Purrington, Mei-Chin Hsieh, Julie Ruterbusch, Angela S. Wenzlaff, Stephanie Pandolfi, Ann Schwartz, Elena Stoffel, Laura Rozek. Survival differences between early onset (50 years) and average onset (≥ 50 years) colorectal cancer among African Americans in metropolitan Detroit abstract. In: Proceedings of the AACR Special Conference in Cancer Research: The Rise in Early-Onset Cancers—Knowledge Gaps and Research Opportunities; 2025 Dec 10-13; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2025;31 (23Suppl): Abstract nr B021.
Lee et al. (Wed,) studied this question.