Abstract PS4-11-16: Treatment Delays and Testing Disparities May Contribute to Racial Differences in Node-Positive ER+/HER2- Breast Cancer Outcomes

Abstract Background: Despite significant advances in breast cancer treatment, racial disparities in outcomes persist. Recent data from the National Cancer Database (NCDB) show Black patients with node-positive (N+) ER+/HER2- breast cancer receiving neoadjuvant chemotherapy (NAC) had worse overall survival (OS) compared to White patients (HR 1.15, p = 0.001) (Moldoveanu 2024). To understand these disparities, we conducted a comparative analysis of N+ ER+/HER2- breast cancer patients treated at a single large academic institution in the Bronx and those represented in the NCDB. Methods: We conducted a retrospective chart review of patients with N+ ER+/HER2- breast cancer (2018-2021) treated with NAC at an institution in the Bronx. Separately, we identified patients meeting the same criteria in the NCDB Participant Use File. Cohorts were analyzed separately, then compared to assess differences. We examined potential drivers of disparities such as molecular assay use, treatment delays, and income. Results: Among the 38,134 patients identified in the NCDB, 65% were White, 16% Black, 11% Hispanic, 4% Asian, and 5% other. Black patients were less likely than White patients to receive Oncotype DX testing (6.9% vs. 8.9%, p < 0.001). Black patients had longer times from diagnosis to the start of chemotherapy (43 vs. 38) and surgery (163 vs. 154 days) (p < 0.001) when compared to White patients. Furthermore, they were 2.6 times more likely to fall into the lowest income quartile (