Patients with clinical stage II or III rectal cancer who were undergoing preoperative RT ( 45 Gy in 25 fractions over 5 weeks plus a boost of 5.4 Gy to 10.8 Gy in three to six daily fractions ) were randomly assigned to one of the following chemotherapy regimens : continuous intravenous infusional fluorouracil ( CVI FU ; 225 mg/m ( 2 ) , 5 days per week ) , with or without intravenous oxaliplatin ( 50 mg/m ( 2 ) once per week for 5 weeks ) or oral capecitabine ( 825 mg/m ( 2 ) twice per day , 5 days per week ) , with or without oxaliplatin ( 50 mg/m ( 2 ) once per week for 5 weeks ) .