High pathologic complete response in HER 2-positive locally advanced breast cancer after primary systemic chemotherapy with weekly docetaxel and epirubicin

Background: To evaluate pathological complete response rate and to identify the predictor of response after primary systemic chemotherapy (PST) with weekly docetaxel and epirubicin for locally advanced breast cancer. Methods: Sixty-three patients with locally advanced breast cancer received three cycles PST on day 1 and 8 of each 3-week cycle with epirubicin and docetaxel (epirubicin 45 mg/m² intravenous bolus, docetaxel 35 mg/m² in 100 ml normal saline infused 1 h), followed by surgery and adjuvant chemotherapy with cyclophosphamide, epirubicin and 5-fluorouracil. The pathological complete response was defined as no invasive carcinoma in breast and axillary nodes after PST. Results: The median tumor sizes (by ultrasound) before and after PST were 6.2 and 2.5 cm, respectively. The negative estrogen receptor (ER) by immunochemical stain was found in 33 (52.4%) patients and HER-2/ neu-overexpression in 12 (19.0%) patients. Clinical overall response rate (ORR) was 89% (95% confidence intervals (95% CI: 81-97), including 38% complete response (95% CI: 26-50), sonographical ORR was 97% (95% CI: 93-100). The pathological complete response were found in 11 patients (18%, 95% CI: 9-27), and 15(24%, 95% CI: 13-35) patients achieved breast only pathological complete response. Nine (27.3%) of thirty-three ER (-) patients and 5 (41.7%) of 12 HER2-positive patients achieved pathological complete response. Conclusion: PST with weekly docetaxel and epirubicin were well-tolerated and very high pathological complete response rate was achieved in HER-2/neu-overexpression tumors.