The local recurrence of rectal cancer is one of the main problem that fail the treatment. The
preoperative neoadjuvant (chemo)radiotherapy has been confirmed to reduce the local
recurrence rate,especially in the advanced rectal cancer. However the local recurrence rate
is low about 10-20% totally,and the integrity of the mesorectum after the operation and
circumferential resection margin(CRM) are the most critical factor for the local
recurrence.So that, the advanced rectal cancer patients with negative CRM and had a complete
mesorectum excision,may not benefit from the neoadjuvant radiation.This trial was mainly
focus on the resectable advanced rectal cancer patients whose preoperative stage was cT3/N+.
These patients will be divided into the lower risk group and higher risk group according the
preoperative CT,Endoscopic ultrasound, and MRI,and carrying out randomized trial in the two
groups respectively.The purpose of this trial is to confirm whether the preoperative
radiotherapy is necessary for all the advanced rectal cancer patients,identify the reason of
the local recurrence,and finally help the making of the treatment decision for the advanced
resectable rectal cancer.