Docetaxel and cyclophosphamide as neoadjuvant chemotherapy in HER2-negative primary breast cancer

Abstract

Background: Docetaxel plus cyclophosphamide (TC) has recently been established as a standard adjuvant chemotherapy regimen for HER2-negative (HER2−) operable breast cancer. However, the efficacy and tolerability of TC as neoadjuvant chemotherapy (NAC) remain unclear. We, therefore, conducted a prospective study to evaluate the efficacy of TC NAC in HER2− primary breast cancer. Methods: Patients who were diagnosed with HER2−, N0–N1, invasive breast cancer between July 2011 and February 2014 and had tumors measuring 1–7 cm were eligible. The subtypes were classified using a core-needle or vacuum-assisted breast biopsy. The efficacy and safety of NAC comprising TC (75 mg/m2 docetaxel and 600 mg/m2 cyclophosphamide, four cycles every 3 weeks) were investigated in a prospective study in patients with HER2− breast cancer. Results: Fifty-two patients were enrolled. Of these, 94.2 % (49/52) completed four cycles of TC. The overall pCR rate was 16.3 % (8/49). The pCR rates for patients with luminal A-like breast cancer [estrogen receptor-positive (ER+), Ki67 index of <20 %, and HER2−], luminal B-like breast cancer (ER+, Ki67 index of >20 %, and HER2−), and triple-negative breast cancer [ER-negative (ER−) and HER2−] were 0 % (0/12), 4.3 % (1/23), and 50.0 % (7/14), respectively. Almost all pCRs occurred in triple-negative breast cancer patients. Conclusions: The pCR rate of TC NAC was not very high despite the high completion rate. TC NAC was effective against the triple-negative subtype, resulting in a higher pCR rate. Therefore, our results indicated that TC NAC showed limited efficacy in luminal subtype breast cancer with the exception of the triple-negative subtype.