Radiation-Induced Heart Disease

Abstract

Cancer incidence and survivorship have had a rising tendency over the last two decades due to better treatment modalities. One of these is radiation therapy (RT), which is used in 20–55% of cancer patients, and its basic principle consists of inhibiting proliferation or inducing apoptosis of cancer cells. Classically, photon beam RT has been the mainstay therapy for these patients, but, in the last decade, proton beam has been introduced as a new option. This newer method focuses more on the tumor and affects less of the surrounding normal tissue, i.e., the heart. Radiation to the heart is a common complication of RT, especially in patients with lymphoma, breast, lung, and esophageal cancer. The pathophysiology is due to changes in the microvascular and macrovascular milieu that can promote accelerated atherosclerosis and/or induce fibrosis of the myocardium, pericardium, and valves. These complications occur days, weeks, or years after RT and the risk factors associated are high radiation doses (>30 Gy), concomitant chemotherapy (primarily anthracyclines), age, history of heart disease, and the presence of cardiovascular risk factors. The understanding of these mechanisms and risk factors by physicians can lead to a tailored assessment and monitorization of these patients with the objective of early detection or prevention of radiation-induced heart disease. Echocardiography is a noninvasive method which provides a comprehensive evaluation of the pericardium, valves, myocardium, and coronaries, making it the first imaging tool in most cases; however, other modalities, such as computed tomography, nuclear medicine, or cardiac magnetic resonance, can provide additional value.

An overview of radiation-induced heart disease

“…Echocardiography is considered the first line in evaluating patients with radiation-induced pericardial disease, and it can detect pericardial thickening, surrounding effusions, and hemodynamic effects of constrictive pericarditis and pericardial tamponade [7]. Cardiac computerized tomography (CT) and cardiac magnetic resonance (CMR) can also be complementary methods for further delineating inflammation, edema, and fibrosis [6].…”

“…Left-sided valves are usually more affected, with the most common abnormality being aortic regurgitation, followed by mitral regurgitation. Aortic stenosis, as well as tricuspid and pulmonary regurgitation, are less common but reported manifestations of RIVHD [7,18,28]. Similar to pericardial disease, prediction models have utilized cardiac substructure exposure percentage and dose to predict the occurrence of valvular disease.…”

“…Cella et al [29,30] showed that the risk of mitral and aortic valve disease increased if a larger volume of the LA and LV received doses > 25-30 Gy. Echocardiography remains the cornerstone of diagnosis for its ability to detect anatomical and functional changes in the valves and their effect on the ventricles [7,25]. With disease progression, patients may require interventional or surgical valve replacement.…”

“…and type of malignancy [6]. For example, there is a 1.7-to 2-fold increase in cardiovascular mortality amongst radiated patients, and the risk further increases to 7.2-fold in those who received radiation before the 1970s [7]. In addition, the incidence of RIHD is higher in lymphoma patients as compared to breast cancer patients, approaching 49.5%-54.5%, with a variable incidence of each subtype of heart disease within each cancer population (0.5%-37% for breast cancer patients vs. 11%-31% for lymphoma patients) [8].…”

Momordica. charantia-Derived Extracellular Vesicles-Like Nanovesicles Protect Cardiomyocytes Against Radiation Injury via Attenuating DNA Damage and Mitochondria Dysfunction

“…With the advances in cancer management, clinicians have seen a remarkable improvement in cancer prognosis. The prolonged overall survival period has driven the recognition of cancer therapy-related adverse effects such as radiation-induced heart disease (RIHD) ( 1 ). As an essential modality for thoracic cancer therapy, radiotherapy (RT) eliminates the tumor, and injuries normal heart cells/tissues.…”