Breast‐conserving therapy is associated with better survival than mastectomy in Early‐stage breast cancer: A propensity score analysis

Background Recent retrospective studies have reported that breast‐conserving therapy (BCT) led to improved overall survival (OS) than mastectomy in some populations. We aimed to compare the efficacy of BCT and mastectomy using the SEER database. Materials and methods Between 2010 and 2015, 99,790 eligible patients were identified. We included early‐stage breast cancer patients with 5cm or smaller tumors and three or fewer positive lymph nodes in our study. We compared the OS and breast cancer‐specific survival (BCSS) results among patients with BCT and those with mastectomy. Kaplan‐Meier plots, Cox proportional hazard regressions, competing risk analysis, and multivariate regressions were used to evaluate the outcomes. Propensity‐score matching was used to assemble a cohort of patients with similar baseline characteristics. Results In our study, 77,452 (77.6%) patients underwent BCT and 22,338 (22.4%) underwent mastectomy. The 5‐year OS rate was 94.7% in the BCT group and 87.6% in the mastectomy group, and the 5‐year BCSS was 97.2% in the BCT and 94.3% in the mastectomy group. Multivariate analysis in the matched cohort showed that women underwent mastectomy was associated with worse OS (Hazard ratio (HR) = 1.79; 95% confidence intervals (CIs) = 1.59–2.02, p