Breast-conserving surgery following neoadjuvant therapy-a systematic review on surgical outcomes

PURPOSE: Neoadjuvant chemotherapy (NACT) is increasingly used in breast cancer treatment. One of the main goals of NACT is to reduce the extent of local surgery of the breast and axilla. The aim of this study was to determine surgical outcomes for patients receiving breast-conserving therapy (BCT) after NACT, including margin status plus secondary surgeries, excision volumes, and cosmetic outcomes. METHODS: A systematic review was performed in accordance with PRISMA principles. Pubmed, MEDLINE, Embase, and the Cochrane Library were searched for studies investigating the results of BCT following NACT. The main study outcomes were margin status, additional local therapies, excision volumes, and cosmetic outcomes. Non-comparative studies on NACT were also included. Exclusion criteria were studies with less than 25 patients, and studies excluding secondary mastectomy patients. FINDINGS: Of the 1219 studies screened, 26 studies were deemed eligible for analysis, including data from 5379 patients treated with NACT and 10,110 patients treated without NACT. Included studies showed wide ranges of tumor-involved margins (2–39.8%), secondary surgeries (0–45.4%), and excision volumes (43.2–268 cm(3)) or specimen weight (26.4–233 g) after NACT. Most studies were retrospective, with a high heterogeneity and a high risk of bias. Cosmetic outcomes after NACT were reported in two single-center cohort studies. Both studies showed acceptable cosmetic outcomes. INTERPRETATION: There is currently insufficient evidence to suggest that NACT improves surgical outcomes of BCT. It is imperative that clinical trials include patient outcome measures in order to allow monitoring and meaningful comparison of treatment outcomes in breast cancer.