Association of Cardiovascular Disease Risk Factors with Late Cardiotoxicity and Survival in HER2-positive Breast Cancer Survivors

PURPOSE: Breast cancer and cardiovascular (CV) diseases often share the same risk factors. It is increasingly important to identify risk factors for CV events in patients with high-risk breast cancer and explore optimal treatment regimens. EXPERIMENTAL DESIGN: Early HER2-positive breast cancer patients at our institution between January 1998 and October 2009 were reviewed. Primary outcome was late-severe-CV-event-free survival, and late severe CV events were defined as cardiovascular death, cardiomyopathy, symptomatic heart failure, and myocardial infarction developing 2+ years after breast cancer diagnosis. Kaplan-Meier plots, Cox proportional hazard regressions, and restricted mean survival time were used to evaluate outcomes. RESULTS: We identified 2,448 consecutive eligible patients with a median follow-up time of 111.0 months (interquartile range, 52.0-151.8 months). One hundred and thirty-six patients had late severe CV events and 752 died of any cause [533 (70.9%) died of primary breast cancer; 12 (1.6%) died of cardiovascular disease]. Hypertension [HR, 1.546; 95% confidence interval (95% CI), 1.030-2.320; P = 0.036] and history of coronary artery disease (CAD; HR, 3.333; 95% CI, 1.669-6.656; P < 0.001) were associated with worse late-severe-CV-event-free survival. Anthracycline-containing regimens (HR, 1.536; 95% CI, 0.979-2.411; P = 0.062) was not a significant risk factor for CV events in multivariate analysis. Regimens containing both anthracycline and anti-HER2 therapy were prognostic for better OS (HR, 0.515; 95% CI, 0.412-0.643; P < 0.001). CONCLUSIONS: Hypertension and CAD history were independent prognostic factors for late severe CV events. Adding anti-HER2 agents to anthracycline-containing regimens did not substantially increase the risk for late severe cardiotoxicity and conferred better overall survival.