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 (46, 277, p 0. 001), a status also associated with longer times to chemotherapy (42 vs. 36 days) and surgery (163 vs. 159 days) (p 0. 001) compared to those earning over 74, 063 annually. Patients in the slowest quartile for time to chemotherapy had a lower rate of nodal response compared to those in the fastest quartile (27% vs. 34%, p 0. 001). Of the 99 patients treated at the Bronx institution, 48% were Hispanic, 31% Black, 16% White, 2% Asian, and 3% other. Bronx patients (83. 8% non-White) experienced longer times from diagnosis to chemotherapy (48 vs. 39 days, p = 0. 02) and to surgery (217 vs. 156 days, p 0. 001) compared to the NCDB. Conclusion: Our findings highlight that delays in treatment initiation and lower utilization of Oncotype DX among Black patients may contribute to racial disparities in breast cancer outcomes. As demonstrated by the NCDB and Bronx cohort, non-White and low-income patients experience delays in initiating treatment and undergoing surgery when compared to White patients and higher-income patients. In the Bronx cohort, these delays were more pronounced than those observed in the national dataset. Longer time to chemotherapy was associated with reduced nodal response rates, underscoring the potential clinical consequences of these delays. Though these delays may in part be due to structural determinants of health, further studies are needed to identify all contributing factors. Citation Format: L. Coe, M. Wood, S. Jao, F. Bhimani, M. Sheckley, E. Ravetch, A. Gupta, S. Feldman, M. McEvoy. Treatment Delays and Testing Disparities May Contribute to Racial Differences in Node-Positive ER+/HER2- Breast Cancer Outcomes abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32 (4 Suppl): Abstract nr PS4-11-16.