Since these guidelines were last updated in 2011, there has been ongoing research and development in endoscope design, aimed at improved detection of colonic neoplasia, reducing miss rates, and enhancing lesion characterisation for diagnosis. These new features include technologies aimed at increased mucosal views through wider angle visualisation and ultra-magnification endoscopic systems allowing in vivo histological assessment. Many of these technologies are now commercially available. However, there is still a need for further studies, including cost-benefit analysis, before they can be adopted as mainstream practice. Established technologies include high-definition colonoscopy, wide-angle colonoscopy and electronic chromoendoscopy, such as narrow band imaging (NBI; Olympus), flexible spectral imaging colour enhancement such as Fujinon intelligent chromoendoscopy (FICE) and i-SCAN (Pentax). These technologies are now incorporated into all of the latest generation colonoscopes, with high-definition white-light endoscopy (WLE) now the standard of care in routine colonoscopy.
Overview of evidence (non-systematic literature review)[edit source]
No systematic reviews were undertaken for this topic. Practice points were based on selected evidence and guidelines (see Guideline development process).
Extra-Wide-Angle-View colonoscopy[edit source]
Wide angle colonoscopy with vision of 170° has become standard in the latest generation colonoscopes. Despite the aim of improving the detection of lesions hidden behind colonic folds, all studies in the available literature, with one exception, suggest that wide angle colonoscopes do not significantly reduce polyp miss rates, which have been estimated to be has high as 31% in systematic reviews.
Given these high rates of missed lesions, there has been an emergence of new technologies aimed at reducing miss rates through wider mucosal visualisation up to 330°. These include Third Eye Retroscope and Third Eye Panoramic (Avantis Medical Systems). Fuse Full Spectrum Endoscopy colonoscopy platform (Endo-Choice Inc); and the Extra-Wide-Angle-View colonoscope (Olympus). While many of these technologies have shown promise through increased detection rates over standard forward viewing colonoscopy, none have shown an absolute superiority to standard colonoscopy and therefore cannot be recommended as standard of care. Continued emphasis has been placed on excellent bowel preparation, completed procedures to caecum and methodical, attentive and slow withdrawal as the keys to polyp detection.
Ultra-magnifying technologies[edit source]
In recent years there has been increasing interest in a 'predict-resect-and-discard' policy for management of diminutive polyps. Ultra-magnifying technologies such as confocal light endomicroscopy and endocytoscopy have advanced considerably and are now commercially available. These emerging technologies may offer most in correct histological classification of polyps prior to resection and discard or in surveillance in patients with inflammatory bowel disease (IBD). However, due to cost, time and the expertise required, they are still not part of mainstream practice (see also Recommended techniques for surveillance in IBD patients).
Electronic chromoendoscopy[edit source]
In the era of push-button technologies, electronic chromoendoscopy refers to imaging technologies that result in detailed contrast enhancement of blood vessels, which aids in lesion detection and characterisation. There is now a wide range of available technologies including NBI, FICE and i-scan.
Narrow-band imaging technology is the most commonly used and researched optical digital method of performing image-enhanced endoscopy. First-generation NBI had poor brightness and contrast enhancement, which limited its usefulness. The second-generation NBI, released in 2012, was able to deliver more than one-and-a-half times higher brightness, and twice the viewable distance in the lumen, than the first-generation NBI.
The utility of electronic chromoendoscopy over WLE has been evaluated in four broad areas:
- adenoma detection in individuals at average risk for colorectal cancer
- adenoma detection in hereditary syndromes
- dysplasia detection in IBD
- lesion characterisation.
With respect to adenoma detection in average risk individuals, most studies have compared NBI with WLE. Numerous studies, including multiple meta-analyses, have not demonstrated an advantage for NBI over WLE. Given these poor results, additional studies are required to determine the final application of these modalities in routine endoscopy practice.
In contrast to average-risk populations, in high-risk settings electronic chromoendoscopy has been demonstrated to result in improved detection rates over high-definition WLE.  The European Society for Gastroenterology currently endorses the routine use of high-definition panchromoendoscopy in patients with known or suspected Lynch syndrome or serrated polyposis syndrome – acknowledging, however, that overall evidence remains low.
Narrow-band imaging is the only modality studied in dysplasia detection in IBD and has not been demonstrated to improve detection rates over WLE (see also Recommended techniques for surveillance in IBD patients).
Lastly, lesion characterisation remains an area of promise for electronic chromoendoscopy technologies, with several studies showing high accuracy with negative predictive value >90%. However, these results have not been replicated outside of expert centres.
High-definition colonoscopes should be used routinely, as the mainstay of colonoscopy is a careful white-light examination of the well prepared colon.
Electronic chromoendoscopy should be used for lesion characterisation, but has limited value in lesion detection.
- ↑ Corte CJ, Leong RW. Improving the utility of colonoscopy: Recent advances in practice. J Gastroenterol Hepatol 2016 Jan;31(1):32-44 Available from: http://www.ncbi.nlm.nih.gov/pubmed/26211821.
- ↑ 2.0 2.1 2.2 Gralnek IM. Emerging technological advancements in colonoscopy: Third Eye® Retroscope® and Third Eye® Panoramic(TM) , Fuse® Full Spectrum Endoscopy® colonoscopy platform, Extra-Wide-Angle-View colonoscope, and NaviAid(TM) G-EYE(TM) balloon colonoscope. Dig Endosc 2015 Jan;27(2):223-31 Available from: http://www.ncbi.nlm.nih.gov/pubmed/25251748.
- ↑ Tribonias G, Theodoropoulou A, Konstantinidis K, Vardas E, Karmiris K, Chroniaris N, et al. Comparison of standard vs high-definition, wide-angle colonoscopy for polyp detection: a randomized controlled trial. Colorectal Dis 2010 Oct;12(10 Online):e260-6 Available from: http://www.ncbi.nlm.nih.gov/pubmed/19930146.
- ↑ Pellisé M, Fernández-Esparrach G, Cárdenas A, Sendino O, Ricart E, Vaquero E, et al. Impact of wide-angle, high-definition endoscopy in the diagnosis of colorectal neoplasia: a randomized controlled trial. Gastroenterology 2008 Oct;135(4):1062-8 Available from: http://www.ncbi.nlm.nih.gov/pubmed/18725223.
- ↑ Rex DK, Chadalawada V, Helper DJ. Wide angle colonoscopy with a prototype instrument: impact on miss rates and efficiency as determined by back-to-back colonoscopies. Am J Gastroenterol 2003 Sep;98(9):2000-5 Available from: http://www.ncbi.nlm.nih.gov/pubmed/14499778.
- ↑ Deenadayalu VP, Chadalawada V, Rex DK. 170 degrees wide-angle colonoscope: effect on efficiency and miss rates. Am J Gastroenterol 2004 Nov;99(11):2138-42 Available from: http://www.ncbi.nlm.nih.gov/pubmed/15554993.
- ↑ Hite NH, Margolin DA.. Advances in colonoscopy and screening for colon cancer. Seminars in Colon and Rectal Surgery. 2016;27(4):181-186.
- ↑ Hassan C, Pickhardt PJ, Rex DK. A resect and discard strategy would improve cost-effectiveness of colorectal cancer screening. Clin Gastroenterol Hepatol 2010 Oct;8(10):865-9, 869.e1-3 Available from: http://www.ncbi.nlm.nih.gov/pubmed/20621680.
- ↑ Hassan C, East JE. Can high resolution microendoscopy improve the resect and discard strategy? Endoscopy 2013 Jul;45(7):513-5 Available from: http://www.ncbi.nlm.nih.gov/pubmed/23801312.
- ↑ Repici A, Hassan C, Radaelli F, Occhipinti P, De Angelis C, Romeo F, et al. Accuracy of narrow-band imaging in predicting colonoscopy surveillance intervals and histology of distal diminutive polyps: results from a multicenter, prospective trial. Gastrointest Endosc 2013 Jul;78(1):106-14 Available from: http://www.ncbi.nlm.nih.gov/pubmed/23582472.
- ↑ Nakai Y, Isayama H, Shinoura S, Iwashita T, Samarasena JB, Chang KJ, et al. Confocal laser endomicroscopy in gastrointestinal and pancreatobiliary diseases. Dig Endosc 2013 Aug 28 Available from: http://www.ncbi.nlm.nih.gov/pubmed/24033351.
- ↑ Manfredi MA, Abu Dayyeh BK, Bhat YM, Chauhan SS, Gottlieb KT, Hwang JH, et al. Electronic chromoendoscopy. Gastrointest Endosc 2015 Feb;81(2):249-61 Available from: http://www.ncbi.nlm.nih.gov/pubmed/25484330.
- ↑ Wong Kee Song LM, Adler DG, Chand B, Conway JD, Croffie JM, Disario JA, et al. Chromoendoscopy. Gastrointest Endosc 2007 Oct;66(4):639-49 Available from: http://www.ncbi.nlm.nih.gov/pubmed/17643437.
- ↑ Longcroft-Wheaton G, Bhandari P. Electronic chromoendoscopy. Gastrointest Endosc 2015 Oct;82(4):765 Available from: http://www.ncbi.nlm.nih.gov/pubmed/26385282.
- ↑ Gono K. Narrow Band Imaging: Technology Basis and Research and Development History. Clin Endosc 2015 Nov;48(6):476-80 Available from: http://www.ncbi.nlm.nih.gov/pubmed/26668792.
- ↑ Nagorni A, Bjelakovic G, Petrovic B. Narrow band imaging versus conventional white light colonoscopy for the detection of colorectal polyps. Cochrane Database Syst Rev 2012 Jan 18;1:CD008361 Available from: http://www.ncbi.nlm.nih.gov/pubmed/22258983.
- ↑ Dinesen L, Chua TJ, Kaffes AJ. Meta-analysis of narrow-band imaging versus conventional colonoscopy for adenoma detection. Gastrointest Endosc 2012 Mar;75(3):604-11 Available from: http://www.ncbi.nlm.nih.gov/pubmed/22341105.
- ↑ Sabbagh LC, Reveiz L, Aponte D, de Aguiar S. Narrow-band imaging does not improve detection of colorectal polyps when compared to conventional colonoscopy: a randomized controlled trial and meta-analysis of published studies. BMC Gastroenterol 2011 Sep 23;11:100 Available from: http://www.ncbi.nlm.nih.gov/pubmed/21943365.
- ↑ Pasha SF, Leighton JA, Das A, Harrison ME, Gurudu SR, Ramirez FC, et al. Comparison of the yield and miss rate of narrow band imaging and white light endoscopy in patients undergoing screening or surveillance colonoscopy: a meta-analysis. Am J Gastroenterol 2012 Mar;107(3):363-70; quiz 371 Available from: http://www.ncbi.nlm.nih.gov/pubmed/22186978.
- ↑ Hüneburg R, Lammert F, Rabe C, Rahner N, Kahl P, Büttner R, et al. Chromocolonoscopy detects more adenomas than white light colonoscopy or narrow band imaging colonoscopy in hereditary nonpolyposis colorectal cancer screening. Endoscopy 2009 Apr;41(4):316-22 Available from: http://www.ncbi.nlm.nih.gov/pubmed/19340735.
- ↑ East JE, Suzuki N, Stavrinidis M, Guenther T, Thomas HJ, Saunders BP. Narrow band imaging for colonoscopic surveillance in hereditary non-polyposis colorectal cancer. Gut 2008 Jan;57(1):65-70 Available from: http://www.ncbi.nlm.nih.gov/pubmed/17682000.
- ↑ Kamiński MF, Hassan C, Bisschops R, Pohl J, Pellisé M, Dekker E, et al. Advanced imaging for detection and differentiation of colorectal neoplasia: European Society of Gastrointestinal Endoscopy (ESGE) Guideline. Endoscopy 2014 May;46(5):435-49 Available from: http://www.ncbi.nlm.nih.gov/pubmed/24639382.
- ↑ Buchner AM. The Role of Chromoendoscopy in Evaluating Colorectal Dysplasia. Gastroenterol Hepatol (N Y) 2017 Jun;13(6):336-347 Available from: http://www.ncbi.nlm.nih.gov/pubmed/28690450.
- ↑ Rex DK, Kahi C, O'Brien M, Levin TR, Pohl H, Rastogi A, et al. The American Society for Gastrointestinal Endoscopy PIVI (Preservation and Incorporation of Valuable Endoscopic Innovations) on real-time endoscopic assessment of the histology of diminutive colorectal polyps. Gastrointest Endosc 2011 Mar;73(3):419-22 Available from: http://www.ncbi.nlm.nih.gov/pubmed/21353837.
- ↑ Picot J, Rose M, Cooper K, Pickett K, Lord J, Harris P, et al. Virtual chromoendoscopy for the real-time assessment of colorectal polyps in vivo: a systematic review and economic evaluation. Health Technol Assess 2017 Dec;21(79):1-308 Available from: http://www.ncbi.nlm.nih.gov/pubmed/29271339.
- ↑ Hewett DG, Kaltenbach T, Sano Y, Tanaka S, Saunders BP, Ponchon T, et al. Validation of a simple classification system for endoscopic diagnosis of small colorectal polyps using narrow-band imaging. Gastroenterology 2012 Sep;143(3):599-607.e1 Available from: http://www.ncbi.nlm.nih.gov/pubmed/22609383.