Primary objective:

• Pathological complete response (ypT0N0) rate

Secondary objectives:

• Histopathological R0 resection rate
• Pathological downstaging (ypT0-T2N0) rate
• One month surgical complication rate
• Predictive value of pre-operative MRI for surgical, pathological and clinical outcomes
• Safety
• Local and distant recurrence rates
• Progression-free survival
• Overall survival

• Histologically proven adenocarcinoma of the rectum (Tumour ≤ 12 cm from the anal verge)

• No evidence of distant spread

• No prior therapy for chemotherapy or radiation therapy for rectal cancer

• Patient considered locally advanced by MRI:

  • Tumour beyond mesorectal fascia, or
  • Tumour ≤ 2mm from mesorectal fascia, or
  • T3 tumour < 5cm from anal verge

• For female patient of childbearing potential, neither pregnant nor breastfeeding, and under active contraception

• No peripheral neuropathy > grade1

• ECOG PS ≤ 2

• ANC > 1,500 x 10^9/L

• Platelets > 100,000 x 10^9/L

• Creatinine < 1.5 x IULN

• Bilirubin < 1.5 IULN

• SGPT (ALT) < 2.5 IULN

• No pre-existing condition which would deter chemoradiotherapy

• No uncontrolled diarrhoea or fecal incontinence

• No significant small bowel (> 200cc or 6X6X6cm) delineated within the radiation fields

• No other serious uncontrolled concomitant illness

• Informed consent signed

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.