Summary Background Although colonoscopy is the accepted standard for detection of colorectal adenomas and cancers, many adenomas and some cancers are missed. To avoid interval colorectal cancer, the adenoma miss rate of colonoscopy needs to be reduced by improvement of colonoscopy technique and imaging capability. We aimed to compare the adenoma miss rates of full-spectrum endoscopy colonoscopy with those of standard forward-viewing colonoscopy. Methods We did an international, multicentre, randomised trial at three sites in Israel, one site in the Netherlands, and two sites in the USA between Feb 1, 2012, and March 31, 2013. Patients aged 18–70 years referred for colorectal cancer screening, polyp surveillance, or diagnostic assessment underwent same-day, back-to-back tandem colonoscopy with standard forward-viewing colonoscope and the full-spectrum endoscopy colonoscope. The patients were randomly assigned (1:1), via computer-generated randomisation with block size of 20, to which procedure was done first. The endoscopist was masked to group allocation until immediately before the start of colonoscopy examinations; patients were not masked. The primary endpoint was adenoma miss rates. We did per-protocol analyses. This trial is registered with ClinicalTrials.gov, number NCT01549535. Findings 197 participants were enrolled. 185 participants were included in the per-protocol analyses: 88 (48%) were randomly assigned to receive standard forward-viewing colonoscopy first, and 97 (52%) to receive full-spectrum endoscopy colonoscopy first. By per-lesion analysis, the adenoma miss rate was significantly lower in patients in the full-spectrum endoscopy group than in those in the standard forward-viewing procedure group: five (7%) of 67 vs 20 (41%) of 49 adenomas were missed (p<0·0001). Standard forward-viewing colonoscopy missed 20 adenomas in 15 patients; of those, three (15%) were advanced adenomas. Full-spectrum endoscopy missed five adenomas in five patients in whom an adenoma had already been detected with first-pass standard forward-viewing colonoscopy; none of these missed adenomas were advanced. One patient was admitted to hospital for colitis detected at colonoscopy, whereas five minor adverse events were reported including vomiting, diarrhoea, cystitis, gastroenteritis, and bleeding. Interpretation Full-spectrum endoscopy represents a technology advancement for colonoscopy and could improve the efficacy of colorectal cancer screening and surveillance. Funding EndoChoice.

CVE is a superior and more sensitive procedure than barium follow-through and entero-CT in establishing the diagnosis and estimating the extent of Crohn's disease.

Colonoscopy is the standard method for detection and removal of colorectal adenomas, the precursor lesions of most colorectal cancers [1 -4]. Despite being the most sensitive method, colonoscopy does not fully protect a person from developing future colorectal cancer [5 -10]. This imperfection is for a major part caused by missed precancerous lesions due to inadequate bowel preparation, the presence of flat lesions that are difficult to detect [8,9,11], and the relative difficulty of visualizing lesions on the proximal side of haustral folds and the internal curves of flexures [12,13]. The latter may, at least partly, be caused by the fact that the use of standard 140°and 170°colonoscopes allows visualization of only approximately 90 % of the colonic surface [14]. Moreover, it has been shown that up to twothirds of missed lesions are located on the proximal side of folds [13]. The miss rates of colonoscopy have been widely acknowledged, with back-to-back colonoscopy studies showing polyp and adenoma miss rates of approximately 20 % -25 % in older studies [15] and up to 40 % in more recent studies evaluating novel technologies developed to improve visualization behind folds [16,17]. Alongside the implementation of quality indicators [1,18], technologies such as cap-assisted colonoscopy, virtual chromoendoscopy, Third Eye colonoscopy, and Full Spectrum Endoscopy (Fuse) colonoscopy have been developed to improve adenoma detection [16,17,19,20]. However, some of these techniques have been shown to increase only marginally the detection of adenomas, while others are less practical in use or demand high investments with a change in endoscopy platform [21,22]. Background and study aims: Adenoma miss rate during colonoscopy has become a widely acknowledged proxy measure for post-colonoscopy colorectal cancer. Among other reasons, this can happen because of inadequate visualization of the proximal aspects of colonic folds and flexures. EndoRings (EndoAid Ltd., Caesarea, Israel) is a silicone-rubber device that is fitted onto the distal end of the colonoscope. Its flexible circular rings engage and mechanically stretch colonic folds during withdrawal. The primary aim of this study was to compare adenoma miss rates between standard colonoscopy and colonoscopy using EndoRings. Methods: In this multicenter, randomized, tandem colonoscopy study, we performed same-day, back-to-back colonoscopies with EndoRings followed by standard colonoscopy, or vice versa. Results: After exclusion of 10 patients for protocol violations, 116 patients (38.8 % female; mean age 58.7) remained for analysis. The adenoma miss