Abstract PO4-27-03: Real-World Evidence: Impact of Margin Involvement on Overall Survival Following Breast Cancer Surgery – A Single-Center Analysis at Charité University Medical Center Berlin

Abstract

Abstract Introduction: Limited data is available regarding the impact of margin involvement following surgery for early-stage breast cancer on distant recurrence and overall survival (OS). We therefore conducted a retrospective single-center analysis to provide further real-world evidence of margin status on OS. Methods: We systematically evaluated patients who underwent surgical intervention for early breast cancer or carcinoma in situ at Charité University Medical Center Berlin between 2006 and 2022. Our study cohort included individuals with a minimum follow-up period of 6 months and documented margin status. Patients with secondary tumors were excluded from this comprehensive analysis. Results: In our analysis, we included a total of 3767 patients, with a median follow-up duration of 72.2 months. Among these, 3443 patients underwent surgery for invasive breast cancer, while 324 patients underwent surgery for carcinoma in situ. The median overall survival (OS) for the entire cohort was 63.7 months. Specifically, patients who achieved clear margins after primary surgery exhibited a median OS of 63.5 months (n=3068), and those with free margins after secondary surgery had a median OS of 65.2 months (n=610). Conversely, patients with definitively involved margins experienced a shorter median OS of 58.6 months (n=89). The multivariate analysis revealed a statistical trend toward adverse survival outcomes for patients with definitive involved margins (Hazard Ratio 1.55; 95% CI: 0.93-2.56; p=0.090), with no statistically significant difference observed between clear margins following primary or secondary surgery. Notably, patients who underwent breast-conserving surgery demonstrated a significantly improved OS (HR 0.45; 95% CI 0.37-0.45; p< 0.001). Higher rates of margin involvement were observed in patients with hormone receptor-positive tumors and carcinoma in situ, while lower rates were noted in triple-negative breast cancer and after neoadjuvant chemotherapy. Implication: Our findings suggest that involved margins may be associated with a limited overall survival. Notably, patients who underwent breast-conserving therapy exhibited more favorable outcomes in our analysis, underscoring the oncologic safety of this procedure. Citation Format: Maximilian Heinz Beck, Karoline Weiler, Sophia Ossmann, Verena Kiver, Jens-Uwe Blohmer. Real-World Evidence: Impact of Margin Involvement on Overall Survival Following Breast Cancer Surgery – A Single-Center Analysis at Charité University Medical Center Berlin [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 PO4-27-03.