LAUSR

158Background: To prevent cardiac toxicity after chemoradiotherapy for esophageal cancer (EC), decrease of high irradiation dose to the heart without expanding the volume of lung irradiated low dose is needed, but this is not easy under the conventional techniques. Purpose of this study is to investigate the utility of volumetric modulated arc therapy using automated-radiotherapy planning software (auto-VMAT) to solve this issue. Methods: In this simulation study, data of 12 patients with stage I-III ECs previously treated by 3D-conformal radiotherapy (3DCRT) was used. We performed auto-VMAT planning using commercially available ‘Pinnacle3 Auto-Planning’ software. Targets for gross tumor (PTV1) and elective nodal region (PTV2), and organs at risk (OARs: lung, heart, left ventricle, epicardium, left pleura, liver and spinal cord) were delineated. Multi-portal beams were used for 3DCRT and dose description was 40 Gy in 20 fractions for PTV1+2 and 20 Gy in 10 fractions-boost for PTV1. We used the simultaneou...