The study was never started due to lack of staff

The main objective of this study is to offer and evaluate an interim triage approach for patients waiting for surveillance colonoscopies. This will reduce the waiting period and the psychological stressors for our patients and from a scientific point of view allow us to compare the yield of findings for each approach.

This study will randomize patients (with low-risk findings in the initial colonoscopy) waiting for a surveillance colonoscopy into a follow-up with either FIT, CT colonography or colonoscopy. This approach will speed up the time for an exam for our patients and allow us to gather important data on the yield of significant findings when using FIT vs CT colonography vs colonoscopy for the surveillance exam.

All patients with positive FIT or CT colonography results will undergo subsequent colonoscopy. 300 patients will be randomized to 1:1:1 into 3 groups:

Group 1: patients will undergo Colonoscopy, findings will be documented and their participation in the study will end there. The findings of the colonoscopy will be addressed according to the institution's guidelines.

Group 2 will undergo fit testing if the fit test is positive: patients will have a subsequent colonoscopy within 3 months. Findings will be documented and participation in the study will end there. The findings of the colonoscopy will be addressed according to our institution's guidelines. If Fit test is negative patient will leave the study and will have a follow-up colonoscopy in one year.

Group 3 will have CT colonography. If CTC is positive: patients will have a subsequent colonoscopy within 3 months. Findings will be documented and participation in the study will end there. The findings of the colonoscopy will be addressed according to our institution's guidelines. If CTC is negative for polypoid lesions, the patient will leave the study and will have a follow-up 5 years after with a control colonoscopy.

All CT colonography and FIT tests analysis for patients will be performed as per the standard of care. Patients with suspicious lesions in CT colonography and positive FIT results will be redirected for colonoscopy and prioritized as P3 (Meaning endoscopy has to be done within 3 months).

Polypectomy specimens will be sent for pathological examination according to the standard of care and institutional routine practice. Pathology results will be followed up.

Inclusion Criteria:

- people with referral sheets for surveillance colonoscopies : meaning 3 or 5 years after the initial colonoscopy.

Exclusion Criteria:

• known or suspected acute diverticulitis
• ulcerative colitis
• Crohn's disease
• toxic megacolon
• acute abdominal pain
• familial polyposis syndrome
• coagulopathy
• poor general health (defined as an American Society of Anaesthesiologists class >3)
• patients presenting for emergency colonoscopies
• patients incapable of lying flat on their back for the duration of the CT colonography due CHF or other predispositions
• patients with a personal history of CRC
• patient undergoing colonoscopy for surveillance after EMR or ESD procedures
• patients diagnosed with a CRC or a metastatic cancer
• patients with a history of contrast allergies
• Patients referred for polypectomy