To Örebro University

Introduction: The standard surgical management of ipsilateral breast cancer recurrence (IBCR) in patients previously treated with breast-conserving surgery (BCS) and radiotherapy (RT) is mastectomy. Recent international guidelines provide conflicting recommendations. The aim of this study was to perform a systematic literature review and meta-analysis of the oncological outcomes in patients with IBCR treated with repeat BCS (rBCS).

Methods: The MEDLINE and EMBASE databases were searched for relevant English-language publications, with no date restrictions. All relevant studies providing sufficient data to assess oncological outcomes (second local recurrence [LR] and overall survival [OS]) of rBCS for the management of IBCR after previous BCS and RT were included (PROSPERO registration CRD42021286123).

Results: Forty-two observational studies met the criteria and were included in the analysis. The pooled second LR rate after rBCS was 15.7% (95% confidence interval [CI] 12.1-19.7), and 10.3% (95% CI 6.9-14.3) after salvage mastectomy. On meta-analysis of comparative studies (n = 17), the risk ratio (RR) for second LR following rBCS compared with mastectomy was 2.103 (95% CI 1.535-2.883; p < 0.001, I-2 = 55.1%). Repeat RT had a protective effect (coefficient: - 0.317, 95% CI - 0.596 to - 0.038; p = 0.026, I-2 = 40.4%) for second LR. Pooled 5-year OS was 86.8% (95% CI 83.4-90.0) and 79.8% (95% CI 74.7-84.5) for rBCS and salvage mastectomy, respectively. Meta-analysis of comparative studies (n = 20) showed a small OS benefit in favor of rBCS (RR 1.040, 95% CI 1.003-1.079; p = 0.032, I-2 = 70.8%). Overall evidence certainty was very low.

Conclusions: This meta-analysis suggests rBCS could be considered as an option for the management of IBCR in patients previously treated with BCS and RT. Shared decision making, appropriate patient selection, and individualized approach are important for optimal outcomes.