Background: Our group previously published data showing that patients could be stratified by constructed molecular subtype with respect to locoregional recurrence (LRR)-free survival after neoadjuvant chemotherapy and breast-conserving therapy (BCT). That study predated use of trastuzumab for human epidermal growth factor receptor 2 (HER2)-positive patients. The current study was undertaken to determine the impact of subtype and response to therapy in a contemporary cohort. Methods: Clinicopathologic data from 751 breast cancer patients who received neoadjuvant chemotherapy (with trastuzumab if HER2+) and BCT from 2005 to 2012 were identified. Hormone receptor (HR) and HER2 status were used to construct molecular subtypes: HR+/HER2− (n = 369), HR+/HER2+ (n = 105), HR−/HER2+ (n = 58), and HR−/HER2− (n = 219). Actuarial rates of LRR were determined by the Kaplan–Meier method and compared by the log-rank test. Multivariate analysis was performed to determine factors associated with LRR. Results: The pathologic complete response (pCR) rates by subtype were as follows: 16.5 % (HR+/HER2−), 45.7 % (HR+/HER2+), 72.4 % (HR−/HER2+), and 42.0 % (HR−/HER2−) (P < 0.001). Median follow-up was 4.6 years. The 5-year LRR-free survival rate for all patients was 95.4 %. Five-year LRR-free survival rates by subtype were 97.2 % (HR+/HER2−), 96.1 % (HR+/HER2+), 94.4 % (HR−/HER2+), and 93.4 % (HR−/HER2−) (P = 0.44). For patients with HR−/HER2+ disease, the LRR-free survival rates were 97.4 and 86.7 % for those who did and those who did not experience pCR, respectively. For patients with HR−/HER2− disease, the LRR-free survival rates were 98.6 % (pCR) versus 89.9 % (no pCR). On multivariate analysis, the HR−/HER2− subtype, clinical stage III disease, and failure to experience a pCR were associated with LRR. Conclusions: Patients undergoing BCT after neoadjuvant chemotherapy have excellent rates of 5-year LRR-free survival that are affected by molecular subtype and by response to neoadjuvant chemotherapy.
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