Abstract PO5-09-06: Outcomes of breast cancer in a minority-enriched population treated at a large safety-net system: Is site of care a predictor of poor outcomes?

Abstract Background: Breast cancer outcomes in the United States continue to improve, but sociodemographic disparities remain prevalent and impact care delivery and outcomes in vulnerable populations. Safety-net health systems are intended to address inequities by providing access to care for the uninsured/underinsured. Care delivery in a safety-net setting is often inherently complicated by limited resources at these institutions. Here, we present the overall survival (OS) data of breast cancer patients treated at a large safety-net system, compared to the national average. Methods: Parkland Health (PH) is the safety-net system for Dallas County and is affiliated with the University of Texas Southwestern Harold C. Simmons Comprehensive Cancer Center (NCI-CCC). Electronic medical records of patients diagnosed with invasive breast cancer between 2018 to 2020 at PH were reviewed and data on demographics, treatment, and outcomes were collected. Categorical data was summarized with counts and percentages and continuous data was summarized with median and interquartile range. Statistical comparisons used Chi-square test for categorical data and rank sum test for continuous data with a significance level of 0.05. Survival data was analyzed using Cox proportional hazard model. Data from the National Cancer Database (NCDB) for the same period was used for comparison. Results: Of the 657 patients included in the study, the majority (82.5%) belonged to racial and ethnic minorities (Hispanic 50.2%; Black 32.3%). Compared to the NCDB, PH patients were more often uninsured (67% vs 1.6%) or enrolled on Medicaid (14.5% vs 6.9%), and less often on Medicare (8.5% v. 43%) (p 0.01). Triple negative breast cancer (TNBC) phenotype and late-stage diagnosis (stage III/IV) rates were higher at PH compared to NCDB (TNBC 22.8% vs 10.7%, p 0.01; late stage 30.6% vs 13.2%, p 0.01). At a median follow up of 33 (range 24-43) months in PH and 28 (range 21-36) months in NCDB, the unadjusted OS for the PH population was 86.3% vs 92.6% for the NCDB population (p 0.01). Within the PH population, Black race, higher stage, and TNBC were associated with decreased OS. There was a significant interaction between Black race and TNBC. When combining all patients (PH+NCDB), site of care (PH) was associated with a higher risk of death from breast cancer (HR 1.467, 95% CI 1.192-1.805, p 0.0005), however, multivariate analysis did not show a significant difference based on site of care. Factors associated with a significantly increased risk of death in this multivariate analysis (corrected for interaction between Black race and TNBC phenotype) included age, late-stage diagnosis, TNBC, Black race, and uninsured status (Table 1). Conclusions: Breast cancer patients treated at PH were more likely to have adverse disease characteristics compared to the NCDB population. When accounting for these risk factors in multivariate analysis, patients treated at PH had similar outcomes compared to the national average. Our findings reinforce the critical role of safety-net systems in promoting health equity and eliminating disparities. Table 1 Citation Format: Sarah Kashanian, Shifa Kanjwal, L. Steven Brown, Andrea Semlow, Mary Hodges, Robyn Cobb, Brad Walsh, Umber Dickerson, Navid Sadeghi. Outcomes of breast cancer in a minority-enriched population treated at a large safety-net system: Is site of care a predictor of poor outcomes? abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-09-06.