Predictors of complete pathological response after neoadjuvant systemic therapy for breast cancer

BACKGROUND: The aim of the current study was to identify predictors of pathologic complete response (pCR) following neoadjuvant therapy. METHODS: From 2000 to 2007, 518 breast cancer patients received neoadjuvant therapy. Data were compared using chi(2) and Fisher's exact tests and multivariate analysis of variance, as appropriate. RESULTS: Of 518 breast cancer patients receiving neoadjuvant therapy, 81 (16%) had pCR (77 of 456 [17%] with chemotherapy, 4 of 62 [6%] with endocrine therapy; P < .05). Four factors were associated with pCR: higher tumor grade (P = .015), lack of estrogen receptor (ER) and progesterone receptor (PR) expression (P < .0001), HER2/neu amplification (P = .025), and negative lymph node status (P < .0001). On multivariate analysis, ER and PR negativity, HER2/neu amplification, and negative lymph node status were found to significantly correlate with pCR. CONCLUSIONS: Patients with ER-negative and PR-negative and HER2/neu-amplified breast cancer phenotypes are more likely to experience pCR to neoadjuvant therapy. Although pCR is more frequently observed following neoadjuvant chemotherapy, it is rare following neoadjuvant endocrine therapy. (C) 2009 Elsevier Inc. All rights reserved.