Long-term Survival Comparison of Repeated Breast-conserving Surgery Versus Mastectomy for Patients with DCIS with Ipsilateral Breast Tumor Recurrence: A Real-world Longitudinal Study

Background: Although patients diagnosed with ductal carcinoma in situ (DCIS) harbor excellent overall survival (OS) after breast-conserving therapy, the evidence regarding to surgical management for ipsilateral breast tumor recurrence (IBTR) is scarce. This study aimed to assess the prognosis of repeated breast-conserving surgery (BCS) versus mastectomy for IBTR in DCIS survivors. Materials and Methods: Herein, 5344 DCIS cases with IBTR were identified during 702,748 person-years of follow-up, 3532 (66.09%) received mastectomy, and 1812 (33.91%) received repeated BCS. Cox regression and competing risk regression were employed to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for OS and breast cancer–specific survival (BCSS), which was respectively calculated within spontaneous and matched cohorts. Results: After adjustment for confounders, no statistically significant survival difference was observed between the repeated BCS and mastectomy for patients with DCIS with IBTR. The stratified analyses further revealed that patients with DCIS with IBTR receiving repeated BCS combined with radiation therapy were associated with both superior OS (HR, 0.79; CI, 0.64-0.98; P =.04) and BCSS (HR, 0.54; CI, 0.33-0.90; P =.02) compared with counterparts undergoing mastectomy. Furthermore, patients with DCIS who were age older than 60 years at IBTR diagnosis benefit from repeated BCS with radiotherapy (HR, 0.44; CI, 0.24-0.84; P =.01) than mastectomy. Conclusion: We suggest that repeated BCS with radiation therapy deserves consideration when DCIS survivors suffered IBTR. The choice of surgical management should be tailored based on patients’ age at IBTR diagnosis and size of recurrent disease.