Salvage Treatment Strategies for Ipsilateral Breast Tumor Recurrence after Breast-Conserving Therapy: a Real-World Study

BACKGROUND: Salvage mastectomy has long been regarded as the standard treatment for ipsilateral breast tumor recurrence (IBTR) following breast-conserving surgery (BCS) combined with radiotherapy. However, the feasibility and oncological outcomes of alternative local treatment strategies-such as repeat breast-conserving surgery (R-BCS) with or without re-irradiation, or mastectomy combined with re-irradiation-remain unclear. MATERIALS AND METHODS: Using data from Surveillance, Epidemiology, and End Results (SEER) database, we retrospectively analyzed female patients who developed IBTR after initial BCS combined with radiotherapy. Overall survival (OS), breast cancer-specific survival (BCSS), cumulative incidence of second IBTR, and cumulative incidence of contralateral breast cancer were compared between patients treated with salvage mastectomy and those receiving alternative local treatment strategies. RESULTS: A total of 4,651 patients were included. After propensity score matching (PSM), all three groups-R-BCS alone, R-BCS with re-irradiation, and mastectomy with re-irradiation-showed comparable OS, BCSS and contralateral breast cancer risk when compared with salvage mastectomy as the reference. Compared with mastectomy, the cumulative incidence of 10-year second IBTR was significantly higher in the R-BCS-alone group (0.36% vs 5.04%, P = 0.002), while no significant differences were observed for R-BCS combined with re-irradiation or mastectomy combined with re-irradiation (P > 0.999 and P = 0.305, respectively). Subgroup analyses suggested that re-irradiation might correlate with inferior survival in triple-negative IBTR. CONCLUSION: For patients experiencing recurrence after breast-conserving therapy, R-BCS combined with re-irradiation represents a viable alternative to salvage mastectomy. R-BCS alone may increase the risk of second IBTR, while the addition of re-irradiation to mastectomy did not provide additional benefit.