Abstract 6234: Association of cultural racism with breast cancer mortality among adults in the United States, 2018-2020

Background: Breast cancer is the most common cause of cancer among women in the United States, with persistent disparities in mortality by race and ethnicity. Given the extent to which systemic racism is inextricably part of the social environment, we evaluated the relationship between cultural racism, a poorly examined but prevalent component of systemic racism, and breast cancer mortality overall and by molecular subtype. Methods: We utilized a novel state-level multi-dimensional latent measure, the cultural racism factor (CRF), incorporating seven indicators (public symbols of the confederacy, online racial animus, racial resentment, anti-immigrant sentiments, lack of White public support for Medicaid expansion, lack of community-oriented policing prevalence, and aggregate implicit bias of White residents; ≤2017 US national data). We applied the CRF in continuous and dichotomized forms (highest vs. lowest two tertiles). Using cancer data from the Surveillance, Epidemiology, and End Results (SEER) Program (2018-2020), we evaluated the associations of CRF with breast cancer mortality via Cox proportional hazards models with clustering by state and adjusting for sociodemographic and clinical characteristics. We examined whether these associations varied by cancer subtype - Luminal A, Luminal B, HER-2 enriched and triple negative (TNBC). Results: Among the 225,991 patients included in this analysis, 62% were Non-Hispanic (NH)-White, 12% were NH-Black, and 16% were Hispanic. Kaplan-Meier curves by CRF category showed higher survival probabilities among patients living in states within the lowest CRF tertile compared to the highest two tertiles (log-rank p<0.0001). For patients with survival times of 10 month or less, those in the highest CRF tertile had 15% higher risk of death relative to patients in the lowest two tertiles after sequentially adjusting for sociodemographic variables (HR: 1.15; 95% CI: 1.01-1.30), and clinical characteristics (HR: 1.15; 95% CI: 1.03-1.27). Additionally, each unit increase in the CRF score was associated with 7% increased hazard of death after adjusting for covariates (HR: 1.07; 95% CI: 1.02-1.11). However, no significant associations were observed among those with longer survival times. In race and ethnicity-stratified models for survival times of 10 months or less, NH-Black (HR: 1.21; 95% CI: 1.10-1.34) and Hispanic (HR: 1.60; 95% CI: 1.13-2.26) patients living in states in the highest CRF tertile had a higher risk of death than their counterparts living in lower CRF states. No significant associations were observed in subtype-stratified models. Conclusions: Our findings highlight that state-level CRF increases the risk of breast cancer mortality among patients with shorter survival periods, potentially linked to delayed diagnosis, other aspects of inadequate health care, or more aggressive disease. Citation Format: Anjali Gupta, Oyomoare L. Osazuwa-Peters, Nancy Krieger, Tyson Brown, Tomi F. Akinyemiju. Association of cultural racism with breast cancer mortality among adults in the United States, 2018-2020 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6234.