After exclusions and matching, two equal groups of 101,118 patients remained. Median follow-up was 42 months. The majority had invasive ductal histology (77%), and node-negative disease (84%). Receptor status included ER-positive (83%), PR-positive (73%), and HER2/Neu-positive (15%). Chemotherapy was received in 38% and endocrine therapy in 71%. Propensity score matching yielded equivalent groups across all target variables. The 5-year overall survival was superior for BCT compared with mastectomy (92.9% vs. 89.7%, p < 0.001; Fig. 1). This survival advantage persisted for both stage I (p < 0.001) and stage II (p < 0.001) disease on subgroup analysis. Fig. 1 Overall survival in female patients with early stage invasive breast cancer (stage I or II) undergoing breast conservation surgery with radiation compared with mastectomy. BCS breast conservation surgery CONCLUSIONS: BCT is associated with superior overall survival compared with mastectomy for early-stage breast cancer using well-matched, contemporary data.