Patients randomly assigned to sequential treatment received fluorouracil 500 mg/m ( 2 ) , epirubicin 75 mg/m ( 2 ) , and cyclophosphamide 500 mg/m ( 2 ) ( FEC-75 ) on day 1 of a 21-day cycle for four cycles followed by paclitaxel 80 mg/m ( 2 ) and trastuzumab 2 mg/kg ( after a 4 mg/kg loading dose ) once per week for 12 weeks , while those randomly assigned to the concurrent treatment group received paclitaxel and trastuzumab once per week for 12 weeks followed by four cycles of FEC-75 ( on day 1 of each 21-day cycle ) and once-weekly trastuzumab , in the same doses as the sequential group .