Feasibility of a third breast-conserving treatment in ipsilateral breast cancer recurrence: A retrospective population-based analysis.

[INTRODUCTION] Breast-conserving surgery (BCS), followed by radiotherapy, is the standard treatment for early-stage breast cancer. In the event of ipsilateral recurrence, total mastectomy is typically recommended. While a second BCS has been explored in selected cases, no data exist on the feasibility of a third breast-conserving treatment (BCT) after two prior recurrences.

[MATERIALS AND METHODS] We conducted a retrospective population-based study using the SEER database (17 registries, 2000-2020; November 2022 submission). Eligible patients were women with non-metastatic breast cancer who underwent three ipsilateral BCS procedures, each separated by at least 12 months. Clinical, pathological, and treatment data were collected for all episodes. Overall survival (OS) and breast cancer-specific survival (CSS) were analyzed from the diagnosis of the third tumor.

[RESULTS] Twelve patients were identified. Median age at the third diagnosis was 82 years. While most tumors were small and hormone receptor-positive, some presented with more advanced features, including one T4b tumor and two node-positive (N+) cases. Histology was predominantly invasive ductal carcinoma. No patients received chemotherapy; two underwent breast re-irradiation following the third BCS. Median follow-up was 43 months (range: 10-108). Two patients (16.7 %) died from breast cancer. Estimated 5-year OS and CSS were both 71.4 % (95 % CI: 44.7-100 %). No clinicopathologic factor was significantly associated with survival.

[CONCLUSION] This is the first study to report the use of three successive breast-conserving surgeries for ipsilateral recurrences. Despite advanced age and occasional high-risk features, outcomes suggest that this approach may be considered in carefully selected patients and warrants further clinical evaluation.