Cardiotoxicity Associated with Trastuzumab Therapy in Taiwan: A Single Medical Center's 5-Year Experience

IntroductionTrastuzumab, a recombinant humanized monoclonal antibody, targets the external domain of HER2 to improve the efficacy of HER2-positive breast cancer treatment and inhibit carcinoma cellular proliferation. The purpose of this study was to identify early changes in cardiac function and dimensional changes in heart size in patients treated with trastuzumab.Materials and MethodsSeventy three female patients with Her2/neu overexpression (IHC 3+/Fish +) in breast cancer underwent echocardiography before and after trastuzumab therapy.ResultsCardiac complications developed in 14 patients (19.2%), including asymptomatic left ventricle systolic dysfunction (n = 12), symptomatic heart failure (n = 2), new asymptomatic left bundle branch block (n = 1), new negative T waves on electrocardiogram (n = 2), pericardial effusion (n = 1), and death (n = 1). No significant deterioration in diastolic function was noted, and right heart diameters and function did not change significantly. Most patients remained in an asymptomatic stage of cardiac disease. A significant decrease in left ventricular ejection fraction (LVEF) was observed in 14 patients (19.2%), and new mitral regurgitation (≥ grade 1) was noted after 3 months of trastuzumab therapy in 7 patients (9.6%).ConclusionsTrastuzumab led to measurable decreases in LVEF (but only 2.7% was symptomatic heart failure) and new mitral regurgitation. Therefore, regular follow-up with echocardiography is essential for early detection and prevention of trastuzumab-induced cardiomyopathy.