Gastroenterology

Gastroenterology

Volume 144, Issue 1, January 2013, Pages 81-91
Gastroenterology

Original Research
Clinical—Alimentary Tract
Real-Time Optical Biopsy of Colon Polyps With Narrow Band Imaging in Community Practice Does Not Yet Meet Key Thresholds for Clinical Decisions

https://doi.org/10.1053/j.gastro.2012.09.054Get rights and content

Background & Aims

Accurate optical analysis of colorectal polyps (optical biopsy) could prevent unnecessary polypectomies or allow a “resect and discard” strategy with surveillance intervals determined based on the results of the optical biopsy; this could be less expensive than histopathologic analysis of polyps. We prospectively evaluated real-time optical biopsy analysis of polyps with narrow band imaging (NBI) by community-based gastroenterologists.

Methods

We first analyzed a computerized module to train gastroenterologists (N = 13) in optical biopsy skills using photographs of polyps. Then we evaluated a practice-based learning program for these gastroenterologists (n = 12) that included real-time optical analysis of polyps in vivo, comparison of optical biopsy predictions to histopathologic analysis, and ongoing feedback on performance.

Results

Twelve of 13 subjects identified adenomas with >90% accuracy at the end of the computer study, and 3 of 12 subjects did so with accuracy ≥90% in the in vivo study. Learning curves showed considerable variation among batches of polyps. For diminutive rectosigmoid polyps assessed with high confidence at the end of the study, adenomas were identified with mean (95% confidence interval [CI]) accuracy, sensitivity, specificity, and negative predictive values of 81% (73%–89%), 85% (74%–96%), 78% (66%–92%), and 91% (86%–97%), respectively. The adjusted odds ratio for high confidence as a predictor of accuracy was 1.8 (95% CI, 1.3–2.5). The agreement between surveillance recommendations informed by high-confidence NBI analysis of diminutive polyps and results from histopathologic analysis of all polyps was 80% (95% CI, 77%–82%).

Conclusions

In an evaluation of real-time optical biopsy analysis of polyps with NBI, only 25% of gastroenterologists assessed polyps with ≥90% accuracy. The negative predictive value for identification of adenomas, but not the surveillance interval agreement, met the American Society for Gastrointestinal Endoscopy–recommended thresholds for optical biopsy. Better results in community practice must be achieved before NBI-based optical biopsy methods can be used routinely to evaluate polyps; ClinicalTrials.gov number, NCT01638091.

Section snippets

Study Site, Participants, Endoscopic Equipment, and General Study Design

Gastroenterologists from a single-specialty practice in Ann Arbor, Michigan, participated in the study. A research coordinator in Ann Arbor entered data into a REDCap (Vanderbilt University) database designed and administered at a data coordination and analysis center at Stanford University (Stanford, CA).

The institutional review boards of St Joseph Mercy Hospital in Ann Arbor, Michigan, and Stanford University approved the study. All authors had access to the study data and reviewed and

Participant Demographics, Study Colonoscopies, and Polyps

Fourteen participants enrolled and completed the ex vivo study phase, and 12 of them entered the in vivo study phase (Table 1). The in vivo study phase included a total of 1673 study colonoscopies and 2596 study polyps (1858 diminutive, 547 small, 177 large, 14 size missing), with adenomas accounting for 62% of diminutive, 72% of small, and 78% of large study polyps (Table 1).

Ex Vivo Pretest and Posttest

Posttest results were missing for 1 subject, and pretest results were missing for 2 subjects. Test scores improved for

Discussion

We assessed whether the high performance levels in optical diagnosis of polyp histology by experts using NBI can be replicated in real-time practice by community gastroenterologists using commercially available equipment. Ex vivo, after completion of a computerized self-learning module, 12 of 13 participants scored >90% correct on a photograph-based posttest. In vivo, 3 of 12 participants achieved accuracy ≥90% in assessing diminutive polyp histology. Learning curves showed considerable

References (29)

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This article has an accompanying continuing medical education activity on page e17. Learning Objective: Upon completion of this CME activity, successful learners will be able to distinguish between the NBI features of adenomatous and non-adenomatous polyps, identify the recommended ASGE PIVI performance thresholds, and demonstrate knowledge of the current performance levels in NBI optical biopsy in routine practice.

Conflicts of interest The authors disclose the following: D. K. Rex has received research support and serves on the speaker's bureau for Olympus Corp. The remaining authors disclose no conflicts.

Funding Supported by a grant from the Division of Gastroenterology at Stanford University School of Medicine.

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