The investigators hypothesize that a primary embolization, 3-4 weeks before surgery, would allow development of vascular collaterality, in particular for the marginal artery which will ensure a better colonic perfusion.

Inclusion Criteria:

• The patient must have given their free and informed consent and signed the consent form
• The patient must be a member or beneficiary of a health insurance plan
• The patient is at least 18 years old and less than 80 years old
• Patient has rectal cancer or sigmoid colon cancer requiring surgical treatment

Exclusion Criteria:

• The subject is participating in another study, or is in a period of exclusion determined by a previous study
• The subject refuses to sign the consent
• It is impossible to give the subject informed information
• The patient is under safeguard of justice or state guardianship
• Patient has a history of abdominal surgery
• Patient suffers from a hemostasis disorder (hemophilia, von Willebrand disease, thrombocytopenia) and is on anticoagulant therapy.
• Patient whose general condition appears too precarious or is taking corticosteroids or immunosuppressants leading to an unacceptable surgical risk.
• Renal insufficiency with clearance <45ml / min
• Known allergy to contrast media
• Patient who had treatment of the abdominal aorta or its branches Reported pregnancy (the existence of effective contraception will be verified for women of childbearing age).
• Anatomical variant at risk or absence of marginal artery highlighted at the time of arteriography.
• Abnormality of the superior mesenteric artery
• Historic occlusion of the inferior mesenteric artery