Percutaneous Endoscopic Gastrostomy Before Definitive Concurrent Chemoradiation Therapy for Esophageal Squamous Cell Carcinoma

"One or two weeks before CCRT, all patients will undergo a percutaneous endoscopic gastrostomy (PEG) to be administered enteral nutrition support(30-35 kcal/kg of energy, 1.2-1.5g/kg of protein and electrolyte supplementation each day). Nutritional supplements will be administered till 1 month after CCRT.~All patients will receive definitive radiotherapy combined with three cycles of S-1 (40mg/2, BID, po) on D1-14, D22-35, D43-56."