Breast-conserving therapy for triple-negative breast cancer.

IMPORTANCE The aggressive triple-negative phenotype of breast cancer (negative for estrogen and progesterone receptors and v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2 [ERBB2] [formerly human epidermal growth factor receptor 2 (HER2)]) is considered by some investigators to be a relative contraindication to breast-conserving therapy. OBJECTIVES To compare outcomes of breast-conserving therapy for patients with triple-negative breast cancer (TNBC) with those of patients with the luminal A, luminal B, and ERBB2 subtypes. DESIGN, SETTING, AND PARTICIPANTS Prospective database review at an academic tertiary medical center with a designated breast cancer center. We included 1851 consecutive patients ages 29 to 85 years with stages I to III invasive breast cancer who underwent breast-conserving therapy at a single institution from January 1, 2000, through May 30, 2012. Of these patients, 234 (12.6%) had TNBC; 1341 (72.4%), luminal A subtype; 212 (11.5%), luminal B subtype; and 64 (3.5%), ERBB2-enriched subtype. EXPOSURE Breast-conserving therapy. MAIN OUTCOMES AND MEASURES The primary outcome measure was local recurrence (LR). Secondary outcome measures included regional recurrence, distant recurrence, and overall survival. RESULTS Triple-negative breast cancer was associated with younger age at diagnosis (56 vs 60 years; P = .001), larger tumors (2.1 vs 1.8 cm; P < .001), more stage II vs I cancer (42.1% vs 33.6%; P = .005), and more G3 tumors (86.4% vs 28.4%; P < .001) compared with the non-TNBC subtypes. Multivariable analysis showed that TNBC did not have a significantly increased risk of LR compared with the luminal A (hazard ratio, 1.4 [95% CI, 0.6-3.3]; P = .43), luminal B (1.6 [0.5-5.2]; P = .43), and ERBB2 (1.1 [0.2-5.2]; P = .87) subtypes. Only tumor size was a significant predictor of LR (hazard ratio, 4.7 [95% CI, 1.6-14.3]; P = .006). Predictors of worse overall survival included tumor size, grade, and stage and TNBC subtype. CONCLUSIONS AND RELEVANCE Breast-conserving therapy for TNBC is not associated with increased LR compared with non-TNBC subtypes. However, the TNBC phenotype correlates with worse overall survival. Breast-conserving therapy is appropriate for patients with TNBC.