2.4  Preoperative chemoradiation therapy protocol and surgical treatments
We used a standard long-course regimen of 5-fluorouracil (5-FU)-based chemotherapy and a total dose of 50.4 Gy of external beam radiation. Preoperative chemotherapy of 425 mg/m2 5-FU per day and 20 mg/m2 leucovorin per day during weeks 1 and 5 of radiotherapy was administered intravenously. After a median interval of 7.8 weeks (interquartile range: 6.4–8.4 weeks) from completion of CRT, all patients underwent radical cancer resection, based on the principles of TME.