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Virtual chromoendoscopy for the real-time assessment of diminutive colorectal polyps: new SHTAC report published

Published: 9 January 2018
Colorectal polyps are growths that can develop in the large bowel

A SHTAC systematic review and economic evaluation of the clinical-effectiveness and cost-effectiveness of virtual chromoendoscopy for the diagnosis of diminutive colorectal polyps is now available from the National Institute for Health Research (NIHR) Journals Library.

Colorectal polyps are growths that can develop in the large bowel. Around one in five people in the UK get bowel polyps. Most are not cancerous, but some types, called adenomas, can become cancerous if not diagnosed and removed. Currently, specialised doctors or nurses, called ‘endoscopists’, use colonoscopy to detect polyps. The endoscopist inserts a flexible tube with a camera on it into the bowel. If a polyp is found, it is removed and sent to a laboratory to examine if it is an adenoma (a process known as histopathology) and an appropriate surveillance interval is then set. In some patients, polyp removal can cause bleeding or a bowel perforation. Some patients also experience anxiety waiting for the laboratory result.

New colonoscopy techniques, called virtual chromoendoscopy, have been developed for diagnosing polyps. Endoscopists can use these techniques to decide in real-time which polyps are adenomas without sending them to histopathology, as has traditionally been done. The endoscopist can then decide whether to remove the polyp or, if confident that it is not an adenoma, leave it in the colon. Virtual chromoendoscopy may also save the NHS money through reducing laboratory costs, and outpatient appointments.

SHTAC conducted a systematic review and economic evaluation of the clinical effectiveness and cost-effectiveness of three virtual chromoendoscopy technologies for diagnosing diminutive (5 mm in size or less) polyps for the National Institute for Health and Clinical Excellence (NICE) Diagnostics Assessment Programme. The technologies were: Flexible Spectral Imaging Colour Enhancement (FICE) (Aquilant Endoscopy/FujiFilm); i-scan (Pentax Medical) and Narrow Band Imaging (NBI) (Olympus Medical Systems). 

Thirty test accuracy studies were included in the systematic review: 24 for NBI, five for i-scan and three for FICE (two studies assessed two interventions). Polyp assessments made with high confidence were associated with higher sensitivity and endoscopists experienced in virtual chromoendoscopy achieved better results than those without experience. The economic evaluation found that NBI, i-scan and FICE are cost-saving strategies compared with histopathology and the number of quality-adjusted life-years gained was similar between histopathology and virtual chromoendoscopy.

SHTAC’s report informed NICE’s guidance to the National Health Service, which recommended that (subject to certain stipulations) virtual chromoendoscopy using NBI, FICE or i-scan can be used to assess polyps of 5 mm in size or less during colonoscopy, instead of histopathology, to determine whether they are adenomatous. The report can be downloaded open access from the NIHR Journals Library website.


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