P6237Clinical utility of echocardiographic left-ventricular ejection fraction monitoring for cardiotoxicity risk assessment in patients with HER2+ early breast cancer undergoing trastuzumab-based therapy

Abstract

Abstract Background Monitoring left-ventricular ejection fraction (LVEF) is a routinely-practiced strategy to survey patients with breast cancer (BC) towards cardiotoxic treatment effects. However, whether the LVEF as a single measurement or as a trajectory over time is truly sufficient to identify patients at high risk for cardiotoxicity is currently debated. Purpose To quantify the prognostic impact of LVEF and its change over time for predicting cardiotoxicity in women with HER2+ early BC. Methods We analyzed 1,136 echocardiography reports from 185 HER2+ early BC patients treated with trastuzumab ± chemoimmunoendocrine therapy in the neoadjuvant/adjuvant setting (Table 1). Cardiotoxicity was defined as a 10% decline in LVEF below 50%. Results Median baseline LVEF was 64% (25th-75th percentile: 60–69). Nineteen patients (10%) experienced cardiotoxicity (asymptomatic n=12, symptomatic n=7, during treatment n=19, treatment modification/termination n=14), Median time to cardiotoxicity was 6.7 months, and median LVEF decline in patients with cardiotoxicity was 18%. One-year cardiotoxicity risk was 7.6% in the 35 patients with a baseline LVEF≥60% and 24.5% in the 150 patients with a baseline LVEF<60% (Hazard Ratio (HR)=3.45, 95% CI: 1.35–8.75, Figure 1). During treatment, LVEF declined significantly faster in patients who developed cardiotoxicity than in patients without cardiotoxicity (1.3%/month vs. 0.1%/month, p<0.0001). A higher rate of LVEF decrease predicted for higher cardiotoxicity risk (HR per 0.1%/month higher LVEF decrease/month=2.50, 95% CI: 1.31–4.76, p=0.005), and cardiotoxicity risk increased by a factor of 1.7 per 5% absolute LVEF decline from baseline to first follow-up (HR=1.70, 95% CI: 1.30–2.38, p<0.0001). Thirty-six patients (19%) developed an LVEF decline of at least 5% from baseline to first follow-up (“early LVEF decline”). One-year cardiotoxicity risk was 6.8% in those without early LVEF decline and a baseline LVEF≥60% (n=117), 15.7% in those without an early LVEF decline and a baseline LVEF<60% (n=65), and 66.7% in those with an early LVEF decline and a baseline LVEF<60% (n=3), respectively (log-rank p<0.0001). Table 1. Baseline characteristics Age (years, median [IQR]) 55 [49–65] Estrogen receptor positive (n, %) 124 (67%) Neoadjuvant setting (n, %) 103 (56%) Figure 1. Risk of Cardiotoxicity. Conclusion Both a single LVEF measurement and the rate of LVEF decrease strongly predict cardiotoxicity in early BC patients undergoing HER2-targeted therapy. Routine LVEF monitoring identifies individuals at high risk of cardiotoxicity that may benefit from more sensitive screening techniques such as strain imaging.