A Study of Neoadjuvant Chemoradiotherapy With 5-FU/Leucovorin (FL) vs. TS-1/Irinotecan in Patients With Locally Advanced Rectal Cancer

This is an open-label, randomized phase II study. Patients will be randomly assigned to either FL or TS-1/irinotecan preoperative chemotherapy regimens by stratification. Patients in FL group will be treated with bolus injections of 5-FU 400 mg/m2/day and LV 20 mg/m2/day for 3 consecutive days every 4 weeks for 2 cycles, and patients in TS-1/irinotecan will be treated with irinotecan 40 mg/m2/day on days 1, 8, 15, 22, 29. TS-1 at a dose of 35mg/m2 was administered orally twice a day after a meal on the day of irradiation (Monday-Friday) concurrent with radiotherapy.