Recent studies suggest survival benefit of breast conservation over mastectomy. We evaluated distant recurrence (DR) rates after breast-conservation therapy (BCT) versus mastectomy in our community-based cancer institute.

A retrospective review of patients undergoing treatment of Stage 0–3 breast cancer from January, 2002 to December, 2011 was performed. We evaluated outcomes between those having BCT versus mastectomy.

We reviewed 4876 patients. There was no significant difference in DR between patients undergoing BCT versus mastectomy in DCIS (n = 904; BCS 521, mastectomy 383; DR = 1/521 vs 1/383; p = 0.09), Stage I (n = 2202; BCT 1505, mastectomy 697; DR = 6/1505 vs 17/697; p = 0.98) or Stage III cancer (n = 417; BCT 87, mastectomy 330; DR = 17/87 vs 59/330; p = 0.50). There was significantly less DR in Stage II patients (n = 1353) undergoing BCT vs mastectomy (32/645 vs 64/708; p = 0.003). Subgroup analysis of Stage II TNBC (n = 198) subgroup analysis showed 104 mastectomy and 94 BCT patients. Those in the BCT group had significantly lower rates of DR (6/94 vs 16/104; p= 0.03) and significantly higher survival (81/94 vs 69/104; p = 0.007) than those undergoing mastectomy. Of Stage II TNBC patients with DR there was no difference in age, lymph node status or tumor size (p > 0.05 for all) in BCT versus mastectomy groups; there was a significant difference in radiation status (94/94 vs. 28/104; p < 0.0001). Radiation was associated with worse outcomes in the mastectomy group (HR 2.32; p = 0.04).

We found significantly less DR in Stage II patients undergoing BCT vs mastectomy. This benefit includes a survival advantage in patients with TNBC undergoing BCT. We could not identify an explanatory factor. Until the difference is understood eligible patients with TNBC should be encouraged to undergo BCT.