Abstract B021: Differences in breast cancer characteristics across demographic groups: Prisma Health Upstate Cohort

Abstract

Racial disparities in breast cancer outcomes persist despite evidence that many tumor features overlap across patient populations. We conducted a retrospective cohort study of 1,688 breast cancer cases treated at the Prisma Health Cancer Institute (2014 to 2022) to evaluate tumor characteristics and presentation patterns across registry- recorded ethnic groups. Black/African American patients had lower ER and PR positivity than White patients, while HER2 amplification was similar. Stage at diagnosis also differed, with fewer Stage IA detections and more late-stage presentation among Black/African American patients. To characterize tumor heterogeneity, we applied multiple correspondence analysis to ER, PR, HER2, stage, and simplified histology in a complete-case cohort (n = 1,421) and performed k-means clustering, identifying four biologically distinct subgroups. Cluster membership was strongly associated with tumor variables and showed a statistically significant but modest association with racial group (Cramér’s V = 0.11), driven by overrepresentation of Black/African American patients in a TNBC-enriched cluster. Overall, these findings suggest inequities in this cohort align more with differences in subtype prevalence and stage at diagnosis than with broad intrinsic divergence in the tumor features evaluated here. Jordan Kinnitt, Brittany Austin, Anna Blenda, Julie Martin, Jeffery Edenfield. Differences in breast cancer characteristics across demographic groups: Prisma Health Upstate Cohort [abstract]. In: Proceedings of the 19th AACR Conference on the Science of Cancer Health Disparities; 2026 Oct 18-21; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2026;35(10 Suppl):Abstract nr B021.