Radical proctectomy with total mesorectal excision

Locally advanced rectal carcinoma raise the issue of both the oncological control, local and general, and the therapeutic morbidity. Surgery alone can cure only one out of two patients, radiochemotherapy improves the local control but the metastatic risk remains about 30% with enhanced postoperative morbidity and poor functional results. The tumor response to preoperative treatment is the major prognostic factor which revealed the aggressiveness of the tumor. To this day, there are no biologic predictive markers for tumor response. The purpose of this trial is to tailor the management according to the early tumoral response after short and intensive induction chemotherapy. MRI volumetric tumor response will be used to distinguish between good responders and bad responders. "Very good" responders will be randomized to either immediate surgery or radiochemotherapy followed by surgery (Standard arm: Cap 50).