Colonoscopy is a valuable tool in reducing the incidence and mortality from colorectal cancer (CRC). Older back-to-back studies evaluating novel endoscopes indicated that conventional colonoscopy misses almost 20% of adenomas. In order to improve the diagnostic accuracy of colonoscopy and to improve the adenoma detection rate (ADR) (a significant marker of quality), efforts have been made to improve endoscopic techniques, the bowel preparation, to keep slower withdrawal time, and to use new technologies and devices. Since 2012, a new accessory device (Endocuff; ARC Medical Design, Leeds, UK), which is mounted on the tip of the colonoscope has been introduced to the market. The Endocuff is a device that can be mounted on the tip of an endoscope and may assist to inspect a greater surface of the colonic mucosa by pulling backwards, flattening, and stretching the colonic folds as the endoscope is gradually withdrawn. Use of this device may achieve better visualization of the bowel lumen, especially behind folds, and improve stability of the instrument on withdrawal.

The aim of this study is to conduct a back-to-back endoscopy study and to evaluate the contribution of Endocuff-assisted colonoscopy to the detection of missed adenomas in a mixed population of colorectal cancer (CRC) screening/surveillance and symptomatic patients.

Inclusion Criteria:

• (i) CRC screening; (ii) post-polypectomy surveillance; (iii) diagnostic assessment (anemia, lower gastrointestinal bleeding, abdominal pain, recent change in bowel habits); and (iv) age over 50 years.

Exclusion Criteria:

• (i) age below 50 years; (ii) the presence of significant comorbidities (American Society of Anesthesiologists [ASA] score III or IV); (iv) recent abdominal surgery; (iv) inflammatory bowel disease; (v) colectomy; (vi) polyposis syndrome; (vii) the presence of acute, severe colitis or a known colonic stricture (viii) boston scale bowel preparation ≥6.

Τhe study is a single center cohort study. Venizeleio General Hospital is a tertiary hospital and the population that will be selected would be residents of the island of Crete.