Colonography Versus Colonoscopy in High Risk Patient

Inclusion Criteria:

Surveillance of patients with a personal history of advanced adenoma or CRC:

* Informed consent obtained
* Age ≥ 18 and ≤ 80 years old
* History of advanced adenomatous polyps
* Or history of non metastatic CRC with curative surgery and without other treatment more than 2 years before enrollment.
* Previous medical examination

Screening of patients with a Family history of CRC at high risk:

* Informed consent obtained
* Age ≥ 18 and ≤ 80 years old
* First degree family history of colorectal cancer diagnosed \<60yrs during the five previous years-Previous medical examination

Exclusion Criteria:

Personal histories

* Age \< 18 or \>80 years old
* history of non adenomatous polyps
* history of Metastatic CRC
* familial adenomatous polyposis, Peutz-Jeghers syndrome, hereditary non polyposis colorectal cancer (HNPCC), juvenile polyposis syndrome
* Familial history of familial adenomatous polyposis
* Personal history of subtotal colectomy (but not of hemicolectomy, to confer to inclusion criteria)
* Colonoscopy with a polyps resection dated more than 5 years and less than 2 years prior to enrollment.
* Enrollment in another protocol
* no health insurance affiliation Family histories
* Age \< 18 or \>80 years old
* Patients with one or several family histories of first degree colorectal cancer occured to unknown age or diagnosed after 60 years old.
* Eligible patients having already undergone colonoscopy screening
* no health insurance affiliation