Abstract P1-09-09: Salvage mastectomy is not always necessary for aggressive subtypes of ipsilateral breast cancer recurrence: A single-institution retrospective study
Authors: Gentile Damiano , Sagona Andrea , Barbieri Erika , Grimaldi Simone Di Maria , Spoto Ruggero , Franceschini Davide , Vaccari Stefano , Vinci Valeriano , Biondi Ersilia , Scardina Lorenzo , Tinterri Corrado 
Published: March 2023

Abstract
Introduction: Patients with triple-negative (TN) or HER2-enriched ipsilateral breast cancer recurrence (IBCR) seem to be excluded from a second breast-conserving surgery (BCS) under the assumption that salvage mastectomy would provide better oncological outcomes. Objectives: The objective of this study was to describe the clinical features of these patients, to compare the two surgical alternatives (salvage mastectomy versus second BCS) in terms of oncological results, and to identify independent factors influencing prognosis and surgical treatment. Methods: We retrospectively reviewed all the consecutive patients with histologically confirmed TN or HER2-enriched IBCR. Disease-free survival (DFS), distant disease-free survival (DDFS), overall survival (OS), and breast cancer-specific survival (BCSS) were analyzed and compared between the two groups. Results: Eighty-five patients were affected by TN or HER2-enriched IBCR, with a median age of 60 years (range, 32-87 years). The majority of patients (72.9%) were treated with salvage mastectomy. There was no significant difference in terms of DFS between patients receiving a second BCS or mastectomy (p=0.596). However, patients undergoing a second BCS had significantly better DDFS, OS, and BCSS compared to mastectomy (p=0.009; p=0.002; p=0.001, respectively). Tumor dimension &lt; 16 mm (78.3% versus 38.7%, hazard ratio (HR)=3.602, 95% confidence interval (95% CI)=1.534-8.459, p=0.003) was found to significantly increase the probability of receiving a second BCS and positively affects recurrence and survival outcomes (DFS: HR=8.065, 95% CI=2.320-28.034, p=0.001; DDFS: HR=17.011, 95% CI=3.853-75.099, p=0.001; OS: HR: 13.881, 95% CI=2.730-70.579, p=0.002; BCSS: HR=36.773, 95% CI=4.579-295.322, p=0.001). Second BCS represents an independent protective factor for OS and BCSS (OS: HR=0.246, 95% CI=0.027-0.697, p=0.002; BCSS: HR=0.313, 95% CI=0.092-0.511, p=0.002). Conclusion: Salvage mastectomy is not always necessary and it does not seem to increase survival compared to a second BCS. This reinforces the concept that the prognosis of TN and HER2-enriched BC recurrence is mainly driven by the biology of the disease, rather than by the extent of surgery. In patients with small (&lt; 16 mm) aggressive subtypes of IBCR, a second conservative approach can still be evaluated and offered, presenting acceptable loco-regional control and survival.
Citation Format: Damiano Gentile, Andrea Sagona, Erika Barbieri, Simone Di Maria Grimaldi, Ruggero Spoto, Davide Franceschini, Stefano Vaccari, Valeriano Vinci, Ersilia Biondi, Lorenzo Scardina, Corrado Tinterri. Salvage mastectomy is not always necessary for aggressive subtypes of ipsilateral breast cancer recurrence: A single-institution retrospective study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-09-09.