Right ventricular function during trastuzumab therapy for breast cancer.

Cardiotoxicity (CDT) is the main adverse effect related to trastuzumab (TTZ). The role of the right ventricle (RV) in this context is not clear. We aimed to evaluate the longitudinal changes in RV function during TTZ therapy and to determine RV function changes associated with subclinical CDT. Breast cancer patients underwent echocardiograms at the beginning of TTZ treatment (Exam 1) and every 3 months during the first year (Exams 2, 3, and 4). Subclinical CDT was defined as ≥ 12% relative reduction of left ventricle global longitudinal strain (LV GLS). Twenty-five women (52.1 ± 13.1 y-o) were included. We found a decrease in LV ejection fraction between the first and fourth exams (Ex1: 64.1% ± 4.9 vs Ex4: 60.9% ± 4.9, p = 0.003) and the LV GLS gradually decreased during follow-up (Ex1: - 20.6% ± 2.0; Ex2: - 19.4% ± 2.1; Ex3: - 19.2% ± 1.8; Ex4: - 19.0% ± 2.1, all p < 0.05). RV GLS changed from baseline to 3 month and to 6 month (Ex1: - 23.9% ± 1.6; Ex2: - 22.5% ± 2.1; Ex3: - 22.5% ± 2.3, all p < 0.05), and the RV Fractional Area Change was lower in the third exam (Ex1: 44.3% ± 6.6 vs Ex3: 39.9% ± 6.0, p = 0.004). We found subclinical CDT in 13 patients (52%); worsening in RV parameters did not differ between those with and without subclinical CDT. In this sample, the RV function decreased during TTZ therapy and the decrease was not associated to the observed LV cardiotoxicity.