Survival and disease-free benefits with mastectomy versus breast conservation therapy for early breast cancer: a meta-analysis

The objective of the present meta-analysis was to estimate the magnitude of survival and disease-free benefits from mastectomy compared with breast conservation therapy (BCT) in patients with early breast cancer. We searched PubMed, Embase, the Cochrane Library, Web of Science, and Chinese biomedical literature database from their inception to May 2015. All the data were independently extracted from the publications by two reviewers. Results regarding the overall survival (OS) and disease-free survival (DFS) in the meta-analysis were expressed as hazard ratios (HRs) with 95 % confidence intervals (CIs). Nine randomized control trials were eligible for final meta-analysis. Meta-analysis showed that mastectomy provided significant benefit in OS compared with BCT (HR 1.09, 95 % CI 1.01-1.19; P = 0.03). Sensitivity analysis gives similar OS estimates (HR 1.12, 95 % CI 1.01-1.25). In the subgroup analysis of patients according to tumor size, the pooled HRs for OS indicated that there is a borderline statistical difference between two arms in the subgroup with tumor size ranging between >= 2 cm and <5 cm (HR 1.09, 95 % CI 1.00-1.19), but subgroup analysis of tumor size <2 cm showed no statistically significant difference in OS (HR 1.08, 95 % CI 0.88-1.33) when comparing the BCT arm with the mastectomy arm. There was no significant difference in DFS between BCT and mastectomy groups (HR 1.08, 95 % CI 0.99-1.18; P = 0.08). Sensitivity analysis also gives similar DFS estimates (HR 1.11, 95 % CI 0.96-1.27). Subgroup analysis indicated that the pooled HRs for DFS did not favor mastectomy arm or BCT arm either in the subgroup with tumor size <2 cm (HR 1.09, 95 % CI 0.78-1.52) or in the subgroup with tumor size ranging between >= 2 cm and <5 cm (HR 1.08, 95 % CI 0.99-1.18) according to tumor size. Five-year OS decreased from 70 to 68 % with BCT. The present meta-analysis indicated that mastectomy might provide slight OS benefit compared with BCT in early breast cancer patients with larger tumor size, but the absolute survival gain is small.