AGA
Management of Diminutive Colon Polyps Based on Endoluminal Imaging

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Diminutive colon polyps, defined as 5 mm or less, are encountered increasingly at colonoscopy. The risk of serious pathology in such polyps is low. There is a risk and cost of resecting all such polyps and sending tissue for pathologic evaluation. Enhancement of endoluminal imaging may enable discrimination of neoplastic vs non-neoplastic polyps. If this discrimination can be performed accurately with high confidence, it may be possible to either resect and discard diminutive adenomas, or inspect and do-not-resect diminutive hyperplastic polyps. In 2011, an expert group recommended thresholds of 90% negative predictive value for adenomas, and 90% accuracy in predicting appropriate surveillance intervals. Since 2011, criteria for polyp discrimination have been published and validated by experts and nonexperts. In vivo studies have been performed to compare endoscopic impression and pathologic diagnosis. An expert panel was convened in late 2014 to review the literature to determine if the proposed thresholds for discrimination can be attained and to recommend the next steps for introducing changes in clinical practice. We conclude that threshold levels can be achieved with several endoscopic image enhancements. The next steps to implementation of practice change include acquiring data on training and competence, determining best practices for auditing performance, understanding patient education needs, and the potential cost benefit of such changes.

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Background

Endoscopic image-enhancement technologies such as chromoendoscopy, NBI, FICE, and i-Scan may enable endoscopists to perform a more intelligent interrogation of polyps found at colonoscopy. Endoluminal interrogation of diminutive polyps (defined as ≤5 mm) could enable endoscopists to distinguish neoplastic (adenoma) from non-neoplastic (hyperplastic) polyps accurately, and make decisions regarding whether the polyp should undergo a biopsy or be resected, and, if so, whether it needs to be sent

What Is the Current State of Practice for Management of Diminutive Colon Polyps at Colonoscopy?

Endoscopists who perform colonoscopies remove most polyps and send the tissue to pathology laboratories for histopathologic interpretation. The endoscopic and histopathologic results then are used to determine appropriate surveillance intervals. Diminutive polyps usually are conventional adenomas, sessile serrated polyps, or hyperplastic polyps. In a meta-analysis including 6280 diminutive polyps from 28 studies, 45% were non-neoplastic.10 In a study of 3744 patients, whose largest polyp was 1

Why should practice change?

An expert panel from the American Society for Gastrointestinal Endoscopy developed topics related to endoscopic innovation (Preservation and Incorporation of Valuable endoscopic Innovation [PIVI]) to help direct endoscopic technology development and research toward dealing with important clinical topics. The 2011 PIVI on real-time endoscopic assessment of diminutive (<5 mm) colorectal polyps focused on setting goals for endoluminal discrimination of neoplastic vs non-neoplastic polyps.1 The

What Is the Current Evidence Supporting the Use of Endoscopic Image-Enhancement Technologies for Diminutive Colon Polyps?

There is strong evidence that discrimination of neoplastic vs non-neoplastic polyps at endoscopy is improved by contrast enhancement with chromoendoscopy or electronic methods.2 NBI has been studied extensively by experts.20, 21, 22, 23, 24, 25, 26 In a meta-analysis,10 evaluating 28 studies based on 6280 polyps that used NBI, the overall sensitivity for NBI diagnosis of colorectal polyps was 91% (95% confidence interval, 87.6–93.5), and specificity was 82.6%. Eight studies measured results

Recommendations of the Expert Panel

The literature shows that PIVI thresholds can be achieved in some, but not all, settings using contrast-enhancement endoscopy. There is evidence that computer training modules can improve performance, but optimal training has not been fully determined. There is ample demonstration that accurate optical biopsy can achieve the aforementioned goals of correct surveillance interval and assessment of ADR, particularly in expert hands.

Recommendations (Table 3) are based on the assumption that

Areas for Further Research

It is not known if one form of electronic image enhancement is better than another. The current evidence suggests that any of the available forms of electronic image contrast enhancement can be effective.

Further work is needed to determine the best methods of training. Recent studies36, 37 have found that currently available training modules do not enable all endoscopists to reach the PIVI threshold for endoluminal diagnosis.

Payers will be interested in cost models that show how this approach

Pragmatic Obstacles That Need to Be Overcome for Implementation

The short-term pragmatic issues for implementation include the following: (1) establishing proper training and credentialing; (2) creating audit tools that will enable periodic checking of accuracy; (3) developing photo-documentation storage to enable future audits; and (4) medical-legal coverage as part of standard practice. Although most endoscopists would acknowledge that diminutive polyps are of little import, there is likely to be a reluctance to change practice. As more evidence

Unintended Consequences of Practice Change

Change in practice is associated with possible unintended consequences. Endoscopists who only recently have socialized the concept of measuring the ADR in their practice may find it troubling to adopt a practice behavior that does not provide confirmation of histology. There is potential gaming of the ADR—nonadenomatous polyps could be called an adenoma with high confidence to satisfy ADR benchmarks. Periodic audits of polyp classification based on high-definition photographs could ensure

Summary

Endoluminal imaging with high-definition colonoscopy plus an electronic image-enhancement method can allow accurate discrimination of neoplastic from non-neoplastic diminutive polyps smaller than 5 mm. The benchmark of greater than 90% accuracy for endoluminal discrimination has now been achieved in many, but not all, clinical trials. These data can be used to make decisions at the time of endoscopy by endoscopists who are trained and competent to perform this assessment. For non-neoplastic

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    This article has an accompanying continuing medical education activity on page e169. Learning Objective–Upon completion of this activity, successful learners will be able to learn about the recent recommendations on the management of diminutive colorectal polyps and learn the value of different endoscopic imaging techniques in managing diminutive colorectal polyps.

    Conflicts of interest These authors disclose the following: David Lieberman has served on the scientific advisory boards for Exact Science, Given Imaging, and Roche Pharmaceutical; Joel Brill owns shares in EndoChoice and has served on the advisory boards of Blue Shield of California, Humana, and United Healthcare; Marcia Canto has performed clinical trial research for C2Therapeutics (2013-2014) and for Cormo Technologies (2014); Daniel DeMarco is a consultant for Olympus Endo-Technology Corp; Brian Fennerty is the American Board of Internal Medicine GI Self Assessment Program Committee Chair; Charles Lightdale has served as a consultant for Boston Scientific, C2Therapeutics, and CSA Medical, and has been a lecturer for NinePoint Medical; Douglas Rex has served as a consultant for Olympus, Endochoice, and Covidien, as a member of the American Society for Gastrointestinal Endoscopy Governing Board, has provided significant research to support Olympus (2014), and has given lectures for Olympus, Endochoice, Covidien, and Boston Scientific; Prateek Sharma serves on the American Society for Gastrointestinal Endoscopy Continuing Medical Education Subcommittee, the World Gastroenterology Organization Chair of Publications Committee, and is a World Gastroenterology Organization Member of the Governing Council; Jeffrey Tokar is consultant for Boston Scientific, US Patent #8609437 “Proteomic biomarkers for the diagnosis and treatment of pancreatic cancer”, Lecturer for Novartis (11/13), DVSGE chairperson, DSMB for Augmenix; Michael Kochman is a stock shareholder, spouse employment, current for Merck, patent sold (8/11) consultant (last 2/14) for Cook Medical, consultant (last 2/12) for Covidien (Barrx), consultant (last 9/12) for Olympus, consultant/stock (Limited Partner) (ongoing) for Dark Canyon Labs, and has served as a consultant (last 11/14) for Boston Scientific Corporation (last 8/15). The remaining authors disclose no conflicts.

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