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Pathological complete response and prognosis in patients receiving neoadjuvant paclitaxel and trastuzumab with and without anthracyclines for stage II and III, HER2-positive operable breast cancer: a single-institute experience.

BACKGROUND
Trastuzumab and various chemotherapy combinations have shown superior results in patients with primary and metastatic breast cancer. However, cardiotoxicity becomes a major adverse event when trastuzumab is used with anthracycline-containing regimens. The purpose of this study was to determine the clinical and pathological efficacy of neoadjuvant chemotherapy (NAC), using trastuzumab and chemotherapy, with or without anthracyclines, for patients with primary breast cancer and human epidermal growth factor receptor 2 (HER2-)-positive tumors.


PATIENTS AND METHODS
A retrospective analysis of 41 patients with stage II and III primary breast cancer and HER2-positive tumors treated with NAC was performed. NAC consisted of weekly paclitaxel plus trastuzumab with (PTA group, n=21) or without anthracycline (PT group, n=20). Patients in the PTA group received four courses of 5-fluorouracil, epirubicin, and cyclophosphamide every 3 weeks followed by concomitant 80 mg/m² paclitaxel and trastuzumab weekly for 12 weeks, and those in the PT group received four courses of 80 mg/m² paclitaxel weekly (days 1, 8, and 15) followed by a 1-week break and trastuzumab weekly (days 1, 8, 15, and 29).


RESULTS
The median age of the patients was 50 years. Of 41 patients, 21 (51%) had a pathological complete response (pCR). Patients with clinical stage II cancer had a higher pCR rate compared with those with clinical stage III. Patients with estrogen receptor (ER)-negative tumors showed a trend toward a higher pCR rate. No significant difference was observed according age, clinical stage, ER status, clinical response, or pathological response between the PTA and the PT groups. The pCR rate of the PTA and the PT groups was 47.6% and 55.0%, respectively. No significant difference in disease-free survival was observed between the two groups at a median follow-up of 32 months.


CONCLUSION
Trastuzumab-containing NAC is effective irrespective of anthracycline use for treating patients with primary breast cancer and HER2-positive tumors.