Abstract 6177: Triple negative breast cancer patients treated with radiation therapy: Improvement in survival and local control with adjuvant chemotherapy compared to neoadjuvant chemotherapy

Purpose: The objective of this study is to evaluate local control and survival rates of node negative triple negative breast cancer patients (TNBCs) treated with radiotherapy (RT) in our institution. Methods: This is a retrospective analysis of 67 TNBCs (2007 - 2017) at an academic state institution who underwent lumpectomy and /or mastectomy (surgery) followed by adjuvant irradiation to median total dose of 50 Gy (range 40.5-50.40 Gy). Chemotherapy was administered in a neoadjuvant (31) or adjuvant setting (36). For all 67 TNBCs, local control (LC), overall survival (OS) and disease free survival (DFS) were estimated using the Kaplan-Meier method. The significance of survival variables were analyzed using the Cox univariate and multivariate proportional hazards model. A p-value of less than 0.05 was considered statistically significant. The SPSS 24.0 software was used for data analysis. Results: The baseline characteristics of all 67 TNBCs were measured with median follow up of 58 months (range 10-142 months). Patients were stratified into two groups (neoadjuvant chemotherapy-RT (31) vs. adjuvant chemotherapy-RT (36)). The median rates for LC, DFS and OS were 27 % vs. 68 % (p= 0.001), 27.2% vs. 63.2 % (p= 0.034), and 63.4% vs. 92.5% (0.001) respectively. On Cox multivariate analysis, patients who received adjuvant chemotherapy were associated with statistically improved significant LC (p= 0.002) and OS (p=0.005). The variables included were: ethnicity (p=0.251), age (p=0.984), BMI (p=0.032), lump boost (p=0.300), TNM (p=0.162) and tumor grade (p=0.336). Conclusion: Among TNBC patients undergoing RT, adjuvant chemotherapy appears to be better than neoadjuvant chemotherapy in determining the clinical outcomes. Citation Format: Mary R. Nittala, Eswar K. Mundra, Satya Packianathan, Divyang Mehta, Maria L. Smith, William C. Woods, Shawn McKinney, Barbara S. Craft, Srinivasan Vijayakumar. Triple negative breast cancer patients treated with radiation therapy: Improvement in survival and local control with adjuvant chemotherapy compared to neoadjuvant chemotherapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6177.