Dose-dependent Radiation-induced Myocardial Damage in Esophageal Cancer Treated with Chemoradiotherapy: A Prospective Cardiac Magnetic Resonance Imaging Study

Abstract Purpose The purpose of this prospective study was to evaluate radiation-induced myocardial damage after mediastinal radiotherapy (RT) using late gadolinium-enhancement (LGE) magnetic resonance imaging (MRI). Methods and materials We enrolled 19 patients with esophageal cancer who were expected to have long-term survival by definitive treatment. They underwent delayed contrast-enhanced MRI (19 patients before treatment, 19 patients 6 months after treatment, and 12 patients 1.5 years after treatment). Dose distribution of the left ventricle (LV) was made using computed tomography (CT), and the dose volume histogram (DVH) of the LV was calculated. Myocardial signal intensities in individual MRIs were normalized by the mean values in regions receiving low doses ( Results The registered patients were treated with concurrent chemoradiotherapy with a median total dose of 60 Gy (50.4-66 Gy). Chemotherapy consisting of cisplatin and 5-fluorouracil was administered. In the population-based dose-response curve, dose-dependent intensity changes progressively increased in regions receiving more than 30 Gy. The averages of relative intensity change at 6 months and 1.5 years after treatment were 1.1% and -1.9% at 20 to 30 Gy and 37.5% and 17.5% at 40 to 50 Gy, respectively. LGE in regions receiving more than 30 Gy was detected in 68% (13/19) of the patients. Conclusions A dose-dependent relationship for myocardial signal intensity change was found by using LGE MRI. It may be necessary to reduce the volume of the myocardium receiving more than 30 Gy.