A Prospective Study About Trastuzumab-induced Cardiotoxicity in HER2-positive Breast Cancer.

Trastuzumab improves therapeutic outcomes among patients with human epidermal growth factor receptor 2-positive breast cancer (BC). However, it is associated with a risk of treatment-induced cardiotoxicity. The aims of this study were to determine the frequency of trastuzumab-induced cardiotoxicity (TIC) in Tunisian patients, to study the effects of trastuzumab on cardiac biomarkers and echocardiographic parameters using the speckle tracking technique and to identify risk factors of occurrence of TIC.Fifty women with newly diagnosed human epidermal growth factor receptor 2-positive BC treated with or without anthracycline followed by taxane and trastuzumab were enrolled, from November 2016 to December 2018, to be evaluated every 3 months during trastuzumab treatment (total of 15 mo) using echocardiograms and blood samples. Left ventricular ejection fraction (LVEF) and peak systolic left ventricular longitudinal myocardial strain were calculated. Ultrasensitive troponin I (TNI) and N-terminal pro-B-type natriuretic peptide (NT pro-BNP) were also measured.LVEF decreased from 62±3.12% to 59±3.3% (P=0.005) over 15 months. Seven patients (14%) developed cardiotoxicity, as defined by the European Society of Cardiology; of these patients, 2 (4%) had symptoms of heart failure. Hypertension, left ventricular longitudinal myocardial strain, Log TNI, and NT pro-BNP measured at the completion of anthracyclines were significantly correlated to TIC occurrence. At multivariate analysis, the degree of LVEF decline was the only independent factor correlated to TIC (hazard ratio=2.4; 95% confidence interval=1.2-6.03; P=0.049). This TIC was reversible in 86% of cases.In patients with BC treated with trastuzumab, in addition to the evaluation of the LVEF, systolic longitudinal strain, TNI, and NT pro-BNP measured at the completion of anthracyclines are useful in the prediction of subsequent TIC.