Maintenance Chemotherapy With S-1, Locally Advanced Esophageal Cancer Receiving Definitive CCRT

"Treatment schedule At 4 to 8 weeks after chemotherapy and radiotherapy ended, maintenance S-1 was administered for up to 12 cycles. A cycle was 3 weeks, with S-1 administrated on days 1 to 14 in each cycle.~The initial dose of S-1 was determined according to the body surface area (BSA): 40 mg twice a day for BSA \< 1.25 m2; 50 mg twice a day for 1.25 m2⩽ BSA \< 1.5 m2; and 60 mg twice a day for BSA ⩾1.5 m2.~Maintenance chemotherapy with S1 was administered for 12 cycles or terminated earlier if there was disease progression, intolerable toxicity, or at the patient's request."