Predictors of pathologic response to preoperative chemotherapy and concurrent radiotherapy for locally advanced breast cancer

Abstract

e11545 Background: Combined modality treatment is essential for acheiving optimal results in the management of locally advanced breast cancer (LABC). Neoadjuvant chemoradiotherapy is considered a promising approach for LABC. Pathologic complete response to neoadjuvant treatment for LABC predicts prolonged survival. Aim: To determine the rate of pathologic complete response (pCR) after neoadjuvant chemotherapy and radiotherapy for locally advanced breast cancer and to identify the predictors of pCR. Methods: Female patients with noninflammatory LABC received neo-adjuvant chemotherapy with concurrent radiotherapy, and then underwent mastectomy and axillary clearance. The pathologic response was analysed with respect to the baseline clinical factors and the receptor status on immunohistochemical studies of the initial biopsy specimen. Results: Of the 296 patients included in the study, 286 underwent mastectomy. Ninety-two (31 %) patients achieved a pCR. The significant predictor of a pCR was Oestrogen receptor negative status (p = 0.025), while progesterone receptor negative status (p=0.069 ), HER2 status (p= 0.62), age (p= 0.074), stage (p=0.6), grade (p=0.86), type of chemotherapy (p=0.37) and number of cycles of chemotherapy (p = 0.23) did not predict for pathologic response. Clinical complete response predicted for a pathologic complete response (p=0.0001). Conclusions: Neoadjuvant concurrent chemoradiotherapy results in good pathologic complete response rates in LABC. High pathologic compete response rates are achieved in patients with endocrine receptor negative disease, with neoadjuvant chemoradiotherapy, which might result in improved outcome in this high risk subset of patients. No significant financial relationships to disclose.