Colonography Versus Colonoscopy in High Risk Patient

Acceptability and Effectiveness of Colonography Compared to Colonoscopy for the Detection of Advanced Adenomas in Patients at High Risk for Colorectal Cancer

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