Response and Prognosis of Docetaxel and Cyclophosphamide as Neoadjuvant Chemotherapy in ER+ HER2− Breast Cancer: A Prospective Phase II Study

Abstract

BackgroundAlthough a docetaxel and cyclophosphomide (TC) regimen without anthracycline as adjuvant therapy became one of the standard regimens especially for ER-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2−) primary breast cancer, the efficacy of TC as neoadjuvant chemotherapy (NAC) is not known. We conducted the prospective trial to assess the efficacy of a TC regimen in the neoadjuvant setting for stage II to III ER+/HER2− primary breast cancer. Patients and MethodsA TC regimen that included 75 mg/m2 of docetaxel and 600 mg/m2 of cyclophosphamide for 4 cycles every 3 weeks was administered as NAC. Primary endpoints are the rate of clinical response (clinical partial response and clinical complete response) and pathologic complete response; secondary endpoints are the disease-free survival and overall survival rates. ResultsThirty (71.4%) of 42 tumors had clinical response. No patient achieved pathologic complete response. At the median follow-up period of 105.2 months (range, 12.1-119.7 months), the disease-free survival rate was 81.6%, and the distant disease-free survival rate was 86.8%. In terms of survival, only 1 patient died during the study period. The overall survival rate was 97.4% during the study period. Patients who developed distant recurrence had a trend to have progesterone receptor-negative or weakly positive compared with those who did not develop any recurrence (85.7% vs. 45.2%; P = .05). ConclusionsOur prospective study showed that a TC regimen as NAC achieved a high clinical response rate in stage II to III ER+/HER2− breast cancer. A TC regimen without anthracycline as NAC might be one of the options for patients with ER+/HER2− breast cancer without high-risk factors including progesterone receptor negativity.