Abstract 10979: Long Term Risk of Coronary Artery Disease in Breast Cancer and Lymphoma Patients After Chemotherapy Plus Radiation Treatment vs Chemotherapy Only

Abstract

Introduction: patients exposed to chest, breast or mediastinal RT, may present with accelerated atherosclerosis and CAD due to diffuse micro and macrovascular fibrosis. However, CAD risk has not been well established in a community-based study. Aims: Describe CAD risk in patients treated with chemotherapy with and without RT and evaluate the cumulative incidence of CAD (coronary revascularization, MI and abnormal stress test and coronary angiogram). Methods: From 1985-2010, we identified 744 patients with a new diagnosis of breast cancer or lymphoma, using the Rochester Epidemiology Project (REP) who received chemotherapy with or without RT. CAD risk was assessed by a proportional hazards model for time to event. RT was treated as a time dependent co-variable, with index date being chemotherapy start date, significance was considered as a p<.05. Characteristics were evaluated by a multivariable Cox model to consider RT and time censoring. Results: 744 patients treated with chemotherapy were identified, of these 488 (65.6%) had breast cancer, 256 (34.4%) lymphoma, and 367 (49%) also received RT. The mean total RT dose was 5.5 ± 1.2 (Gy) for those that had CAD and 5.4 (Gy) ± 1.1 for non-CAD patients, p=0.4. The cumulative incidence of CAD events (accounting for death as a competing risk) at 5 and 10 years of follow-up was 1.9% (CI 1.14-3.2) and 3.06% (CI 2.01-4.7), respectively p<.05 figure1. Baseline differences between those receiving RT or not, were not significant for DM and HTN; however, males and ages 70-79 were less likely to receive RT, table1. In a multivariable model, there was no difference in the CAD outcomes between those with and without RT, HR= 1.21 [0.48-3.06] p=.69, after adjusting for age, gender, DM, and HTN and those <49 y/o had a lower risk of CAD. Table2 Conclusion: In this REP retrospective cohort study, the risk of developing a CAD event was similar between chemotherapy plus RT and chemotherapy only regimens, even after considering gender, age, HTN and DM.