Trastuzumab Cardiotoxicity: Incidence, Risk Factors and the Role of Cardiac Monitoring – The Auckland City Hospital Experience

Abstract

Aim: Trastuzumab is used in the treatment of breast cancer in a selected group of patients. Early studies have reported trastuzumab associated cardiotoxicity. We aim to identify the incidence and risk factors associated with left ventricular ejection fraction (LVEF) changes in this group and review the monitoring protocol. Method: Retrospective review of all patients receiving trastuzumab therapy and had serial echocardiography at Auckland City Hospital between 1 January 2015 and 31 December 2016 were included in this study. Baseline LVEF and changes during treatment were analysed. Results: 295 patients were included (mean: age 54 ± 12 years, BMI 29 ± 7; 21% hypertension, 11% diabetic). 76% had history of anthracycline exposure. Four patients had known ischaemic heart disease or haemodynamically significant valvular heart disease. 1125 echocardiograms were performed as part of the monitoring protocol (average 3.8 echocardiograms per-patient). Mean follow-up was 371 days. LVEF decrease of ≥10% occurred in 33 patients (11.1%), including 11 (3.7%) patients with LVEF decrease below 50%. Two patients developed acute heart failure due to trastuzumab. No death due to heart failure was recorded. The only significant predictor for LVEF decrease of ≥10% during treatment was anthracycline exposure (p = 0.029). Conclusion: Sub-clinical decrease in LVEF occurred in 11.1%. A decrease in LVEF to <50% occurred uncommonly and clinically apparent heart failure occurred rarely. The only significant predictor for LVEF drop during treatment was anthracycline exposure. Management of this higher risk cohort merits further study.