Breast-conserving therapy achieves locoregional outcomes comparable to mastectomy in women with T1-2N0 triple-negative breast cancer.

Background: Conflicting data exist regarding optimum local therapy for early-stage triple-negative breast cancer (TNBC). We examined outcomes according to local treatment type in a large cohort of node-negative TNBC patients.

Methods: A total of 1,242 consecutive patients with TNBC treated at a single institution from 1999 to 2008 were identified. Of these, 646 with pathologic stage T1-2N0 TNBC underwent breast-conserving therapy (BCT) (N = 448) or total mastectomy (TM) without postmastectomy radiation (N = 198) and comprised the study population. Locoregional recurrence (LRR), distant metastasis (DM), and overall recurrence were investigated with a competing risk analysis using Gray's test and multivariable Fine and Gray competing risk regression. Overall survival was assessed using standard Kaplan-Meier methods and a Cox proportional hazards analysis.

Results: Median follow-up was 78.3 months (range 1-156). Eight-one percent of patients received adjuvant chemotherapy. TM patients were younger, were more likely to have lymphovascular invasion, and had larger tumors than patients undergoing BCT (all P ≤ 0.05). The 5-year cumulative incidence of LRR was 4.2 and 5.4 % for patients undergoing BCT and TM, respectively. There was no significant difference in LRR, DM, overall recurrence, disease free survival, or overall survival between groups on univariate analysis, or after adjusting for other variables in multivariate models. Lack of chemotherapy and high tumor stage independently predicted for decreased overall survival (both P < 0.001).

Conclusions: A low, 5-year risk of LRR (4.7 %) was achieved in a large group of women with T1-2N0 TNBC treated with multimodality therapy. BCT was as equally effective as TM for local and distant control.