The cardiac outcomes of radiation therapy to thoracic malignancies: Nationwide analysis.
Authors: Turk Ekrem , Yilmaz Mahir , Obeidat Khaldun , Litvin Rafaella , Uygun Ibrahim , Hammo Hasan , Batra Kunnal 
Published: June 2023

e20565

Background: Radiation therapy (RT) is a therapeutic and palliative treatment option for thoracic neoplasms, including lung cancer (LC), breast cancer (BC), esophageal cancer (EC), and lymphomas. However, chest irradiation's long-term cardiac side effects continue to lead to a wide range of heart conditions. While the immediate side effects are usually in form of pericardial diseases, the long-term complications, usually manifest manifesting in the average of 20 years, include Congestive Heart Failure(CHF), Coronary Artery Disease (CAD), Cardiomyopathy (CMP), Conduction Disorders, Constrictive Pericarditis, and Valvular heart diseases. We aimed to demonstrate most common cardiac outcomes in cancer patients with thoracic RT. Methods: Adult patients with a history of primary Thoracic Malignancies (BC, LC, Thymic Cancer, EC, and Mediastinal Cancer) who had RT are extracted from Nationwide Inpatient Sample 2016 - 2019 by using ICD-10 codes. Other malignancies which can be treated with radiation therapy and all secondary malignancies are excluded from the primary comparison group. Cardiac outcomes are defined as the prevalence of CHF, CAD, CMP, Conduction Disorders, Pericardial diseases, and Valvular heart diseases in the primary group. Multivariate logistic regression analysis was conducted to adjust for confounders. Results: A total of 454.229 adult hospitalizations with primary Thoracic Malignancies who had RT were defined in the NIS 2016-2019 database. The patients with Thoracic malignancies who had RT were older ( mean age 68 vs. 57 years) and had a greater white race population ( %76 vs. %67, P < 0.001). The patients with Thoracic malignancies who had RT have greater odds of developing Chronic Pericarditis [AOR 2, 95% CI 1.9–2.2, P < 0.001], Acute Pericarditis [AOR 2.3, 95% CI 1.9–2.9, P < 0.001], Constrictive Pericarditis [AOR 2.8, 95% CI 2.1–3.7, P < 0.001], Conduction Disorders [AOR 1.3, 95% CI 1.2–1.35, P < 0.001], CAD [AOR 1.24, 95% CI 1.2-1.27, P < 0.001], CHF [AOR 1.44, 95% CI 1.4-1.5, P < 0.001], Valvular Heart Disease [AOR 1.37, 95% CI 1.3-1.4, P < 0.001] and no statistically different odds of developing Cardiac Arrest [AOR 1, 95% CI 0.9-1.10, P = 0.6] or MI [AOR 1.1, %95 CI 1–1.15] compared to the general adult population. Conclusions: The introduction of RT led to improvement in survival for thoracic malignancies. However, radiation-induced cardiovascular disease (CVD) can sometimes limit the benefits from RT. For example, CVD is the most common nonmalignant cause of death in patients with breast cancer and Hodgkin's lymphoma. In this large database study, we found an increase in the prevalence of multiple CVD in patients with a history of RT to the chest, with odds particularly high for pericardial disease, CAD and CHF. These findings highlight the importance of continuing to develop techniques to limit RT-related complications, and ensuring close cardiovascular follow up, possibly including screening.