Objective To analyze the cardiac safety of trastuzumab on HER2 positive breast cancer patients.

Methods Trastuzumab was administrated every three weeks in 185 patients with HER2 positive breast cancer. The initial dose was 8 mg/kg, and the subsequent dose was 6 mg/kg, for 4-36 cycles. The cardiotoxicity of these patients was analyzed.

Results The median treatment was 17 cycles in Her-2 positive breast cancer patients who received trastuzumab. Left ventricular ejection fraction (LVEF) level dropped in 88 cases (47.6%) after trastuzumab treatment; 74 patients (40.0%) occurred valvular regurgitation (new+ aggravation); 16 patients (8.0%) occurred the reduction of diastolic function of left ventricle; 88 patients (47.6%) experienced cardiotoxicity, among which 83 patients experienced gradeⅠcardiotoxicity and five patients experienced grade Ⅱ cardiotoxicity, no patient experienced grade Ⅲ cardiotoxicity.

Conclusion The treatment of trastuzumab on Chinese patients with HER2 positive breast cancer shows a satisfactory cardiac safety. However, the potential cardiotoxicity of trastuzumab should be carefully monitored during therapy.