Cardiotoxicity in patients with breast cancer after modern therapy.

Abstract

e24117 Background: Breast cancer survivors are at increased risk of adverse cardiac events (ACE). Many patient and treatment characteristics, including the use of radiation, anthracyclines, and anti-HER2 therapy, have been reported to affect the rate of ACE. Most prior studies evaluated patients treated with older techniques and therapies, and examined only ischemic events as an endpoint. We report the incidence and risk factors associated with a range of ACE in patients receiving modern systemic and radiation treatments. Methods: Retrospective review identified 235 women with breast cancer who received definitive treatment including radiation between 2017-2023. Coronary artery calcifications (CAC) were defined as density in the heart with ≥130 HU on simulation CT. Event free survival estimates were calculated by Kaplan-Meier method. Uni- and multivariate analyses (MVA) were performed by Cox proportional hazards model. Median follow-up was 3.9 years (range, 0.8-6.9). Results: Patient characteristics are listed in table 1. At 4 years, ACE-free survival was 91.6%. Sixty-six patients had ACE, including arrhythmias (n = 21), valvular disease (17), acute coronary syndrome (9), ventricular dysfunction (20), and pericarditis (1). On MVA, radiation mean heart dose (MHD) > 4 Gy [HR 2.8, 95%CI 1.05-7.5, p = 0.04] and presence of CAC [HR 2.5, 1.2-5.2, p = 0.017] were independently associated with increased ACE. Endocrine therapy was associated with decreased risk (HR 0.4, 0.2-0.8, p = 0.012). Smoking (p = 0.88), hypertension (p = 0.97), diabetes (p = 0.52), treatment with chemotherapy (p = 0.89) including anthracyclines (p = 0.43), treatment with anti-HER2 therapy (p = 0.53), and radiation field (p = 0.65) were not significantly related to ACE in this limited cohort. A subset of patients participated in oncology rehab (n = 43) and there was no clear association with decreased ACE (p = 0.96) in in an exploratory analysis. Conclusions: The rate of ACE is low with modern therapy, even when accounting for a full spectrum of ACE. Consistent with prior studies, we found that higher MHD and CAC are independently associated with ACE, including previously under-reported ACE. Treatment with endocrine therapy was associated with fewer ACE. In this limited cohort with shorter-term follow up, hypertension, diabetes, smoking, and treatment with anthracyclines and anti-HER2 therapy were not associated with ACE, suggesting that these may be less important risk factors. [Table: see text]