Clinical experience of adding intraluminal brachytherapy with traditional applicator after definitive concurrent chemoradiotherapy (CCRT) for local-regional thoracic esophageal cancer is limited due to high complication risk and non-superiority in survival. The innovative applicator can maximize the therapeutic efficacy by reducing dose inhomogeneity in the esophageal wall, which will translate into less over-dosing and less risk of the side effects of fistula or stenosis. The primary goal of this study by using new applicator is to observe the change in local tumor control rate, while secondary goals are treatment related toxicity, progression-free survival, and overall survival.