Breast surgery for patients with de novo metastatic breast cancer: A meta-analysis of randomized controlled trials

The role of breast surgery in the treatment of patients with de novo metastatic breast cancer(dnMBC) remains controversial, with conflicting trial results. We did a meta-analysis to comprehensively investigate and assess whether breast surgery is associated with survival and quality of life outcomes in patients with dnMBC.We systematically searched PubMed, Embase, Google Scholar, Scopus, and Web of Science, from database inception to March 30, 2022, for randomized controlled trials(RCTs) that compared breast surgery or locoregional therapy with non-surgical treatment based on systemic therapy for managing dnMBC.We also reviewed abstracts and presentations from major conference proceedings. We excluded non-randomised trials and considered only papers published in English. The primary outcomes were overall survival(OS),locoregional progression-free survival(LPFS), distant progression-free survival(DPFS), and quality of life(QoL). The quality of RCTs was appraised with the Cochrane Collaboration risk of bias tool. Random-effects model or fixed effects model were used to calculate the effect sizes of included RCTs.Quality of evidence was assessed with GRADE criteria. Data analysis was performed with STATA 17.0. A total of 1018 women from seven randomized clinical trials were included in the analysis. Pooled analyses revealed that compared with systemic therapy, breast surgery was not associated with beneficial outcomes in OS(hazard ratio [HR],0.87; 95%CI,0.68 to 1.11; I² = 53.08 %; p = 0.265),DPFS(HR,1.20; 95%CI,0.94 to 1.54; I² = 86.45 %; p = 0.136), or QoL-global health status (standardized mean difference[SMD],0.08; 95%CI,-0.15 to 0.32; I² = 79.45 %; p = 0.478) and QoL-mental-physical functionality(SMD,-0.19; 95%CI,-0.50 to 0.13; I² = 0.00 %; p = 0.255), but was associated with a benefit in LPFS(HR,0.27; 95%CI,0.19 to 0.38; I² = 84.16 %; p < 0.001). These findings were consistent in subgroup analyses of the timing of surgery, site and number of metastases and tumor molecular subtype. The evidence grade was moderate because of the substantial heterogeneity among studies. Based on the RCTs evidence, we found that breast surgery may benefit locoregional control but does not prolong OS and improve QoL in patients with dnMBC. The Prospero registration number: CRD42020206460.