Influence of Lengthening the Interval Between Radiochemotherapy and Surgery on Complete Pathological Response in Rectal Cancer (GRECCAR6)

• Percentage of pathological complete response after pathological examination of surgical specimen defined by the absence of persistent tumor cell invasion and lymph node (ypT0N0) in group 7 weeks versus 11 weeks in the group [ Time Frame: 6 month ] [ Designated as safety issue: No ]
  

• Rates of clinical response to radio-chemotherapy before surgery, comparison between the two groups (7 versus 11 weeks) [ Time Frame: 6 month ] [ Designated as safety issue: No ]
  
• Rate of tumor regression, comparison between the two groups (7 versus 11 weeks) [ Time Frame: 6 month ] [ Designated as safety issue: No ]
  
• Rates of operative mortality and morbidity at 90 days, comparison between the two groups (7 versus 11 weeks) [ Time Frame: 6 month ] [ Designated as safety issue: No ]
  
• Quality of mesorectum resection, comparison between the two groups (7 versus 11 weeks) [ Time Frame: 6 month ] [ Designated as safety issue: No ]
  
• Rate of sphincter preservation, comparison between the two groups (7 versus 11 weeks) [ Time Frame: 6 month ] [ Designated as safety issue: No ]
  
• Local and distant recurrence rates, comparison between the two groups (7 versus 11 weeks) [ Time Frame: 5 years ] [ Designated as safety issue: No ]
  
• Overall survival and disease-free survival rates, comparison between the two groups (7 versus 11 weeks) [ Time Frame: 5 years ] [ Designated as safety issue: No ]
  

D0: Visit of inclusion and randomization After the end of chemoradiotherapy, the patient is seen in consultation by her / him a surgeon who propose him to participate in the study. At the end of the visit if the patient agrees to participate in it, the investigator at each center will conduct the collection of written consent to the inclusion of the patient. Inclusion will be recorded in the e-CRF by the investigator at each center. Randomization (7 or 11 weeks of delay) is performed by the surgeon via the software module Cleanweb randomization.

M1- 1.5 or M2.5 depending of the group randomisation A consultation with the surgeon is held within 15 days (+/- 5 days) of intervention to check the clinical response (tumor regression in rectal tumor distance from the dentate line) and planify surgery. During this visit, the surgeon noted in the e-CRF, clinical findings of the lesion and the results of further investigations.

Not specific exam is requested in the study.

M2 or M3

Surgical procedure:

The anesthesia consultation is planned before the surgery according to the habits of service. Participation in the study does not alter the anesthetic procedures.The patient is admitted the day before surgery in the surgical ward.

During surgery, the operating data are provided on the e-CRF (digital rectal examination under general anesthesia, type of surgery (anterior resection or abdominal-perineal resection), operative time, intraoperative bleeding, macroscopic appearance of the mesorectum, distance from the distal limit of resection). The postoperative complications are noted by the surgeon in the e-CRF during hospitalization (about 10-15 days), and data reporting pathological (Annex 2).

Pathological examination of the specimen of proctectomy is performed according to recommendations for clinical practice using the standard form (Annex 2). The tumor response is evaluated by inclusion of all residual tumor and the response to chemoradiotherapy is graded with the scale of Rodel (Annex 5). A double reading of slides will be made for each patient by two independent pathologists blinded to the randomization group of the patient.

M2 - M5 or M3 - M6 :

Postoperative follow-up :

Following the intervention, no specific consultation is necessary. At follow-up consultations (1 month, 3 months) the surgeon evaluate the postoperative course, planify the stoma closure, noted the potential adverse events and results of morphological examinations (computed tomography, ultrasound, endoscopy) and biological (markers) eventually prescribed.

M6 - M60 :

Cancer surveillance :

Regular follow-up every 3-4 months fo the first two years and every 6 months for the last remaining 3 years (clinical examination, CT-scan and biological marker (CEA))