Docetaxel, cyclophosphamide and trastuzumab as neoadjuvant chemotherapy in HER2-positive primary breast cancer.

583 Background: The current standard treatment of primary systemic therapy (PST) in HER2+ breast cancer is anthracyclines and/or taxanes combined with trastuzumab which demonstrates high pathological complete response (pCR). The pCR is considered as a predictive marker of prognosis although results are slightly different depending on the hormone receptor status. The efficacy and tolerability of docetaxel, cyclophosphamide and trastuzumab (HER-TC) as neoadjuvant chemotherapy (NAC) remains unclear. We performed a prospective multicenter study of HER-TC NAC in HER2+ primary breast cancer. Methods: Eligible patients had HER2+ invasive breast cancer that measured more than 1cm, less than 7 cm and N0~N1 clinically between July 2011 and February 2014. Four cycles of HER-TC (6 mg/kg loading dose 8 mg/kg, 75 and 600 mg/m2) were administered intravenously every 3 weeks as NAC. We investigated the pCR of primary breast tumors; pCR was defined as no histological evidence of invasive carcinoma, or the appearance of on...