Racial differences in characteristics of early- vs. late-onset colorectal cancer among veterans

Introduction: Colorectal cancer (CRC) accounts for approximately 8% of annual cancer cases in the Veterans Health Administration. While CRC incidence is decreasing, evidence suggests that the incidence among the subset of patients diagnosed before the age of 50 is increasing. The purpose of this work is to compare the clinical and demographic characteristics of veterans with early-onset CRC (age at diagnosis Methods: We conducted a retrospective analysis of national cohort data in the Veterans Affairs Central Cancer Registry on patients diagnosed with CRC between 2001 and 2011. Descriptive statistics (frequencies, medians) were used to compare characteristics among EOC and LOC patients and evaluate black-white differences within both groups of CRC patients. Results: In this cohort of 31,435 patients, 3% (N=966) had EOC, and this proportion was consistent each year. Statistically significant differences between EOC and LOC were noted for race, stage, and tumor location (all p Conclusion: Although we did not find an increasing proportion of EOC over time, EOC was more common in blacks than whites and more common in the distal large bowel. EOC in blacks, however, was more commonly proximal, had less advanced stage at diagnosis but similar survival compared to whites. EOC has distinct clinical characteristics in blacks that may reflect differences in molecular etiology. Our findings emphasize the importance of distinguishing between EOC and LOC to better understand the unique characteristics of early-onset disease and how they might inform prevention and early detection efforts. This abstract is also being presented as Poster C116. Citation Format: Monalesia Chapman, Christina D. Williams, Thomas Ivey Redding, Robin Bartlett, Neeta Chawla, Dawn Provenzale, Michael J. Kelley. Racial differences in characteristics of early- vs. late-onset colorectal cancer among veterans [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr PR11.