No more inclusions

to evaluate the acceptability of CT-colonography compared to colonoscopy for the detection of advanced adenomas in subpopulations at high risk of colorectal.

Secondary objective: to evaluate the medical and economic impact of the implementation of CT- colonography in this setting.Methodology: prospective multicenter randomized controlled trial with direct patient benefitN° of patients to be included: 600 Study follow-up :1 consultation and 3 phone contacts (M1, M6 and M12)Evaluation criteria:Main endpoint: acceptability of the colorectal cancer screening (% of enrolled patients having actually undergone the exploration)Secondary endpoints: - cost/effectiveness ratio of the 2 diagnostic tests with calculation of the economic and medical costs. - number of advanced adenoma detected in each group- number of CRC cases detected in each group

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