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. PATIENTS AND METHODS 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.