Narrow band imaging optical diagnosis of small colorectal polyps in routine clinical practice: the Detect Inspect Characterise Resect and Discard 2 (DISCARD 2) study

Abstract

Background

Accurate optical characterisation and removal of small adenomas (<10 mm) at colonoscopy would allow hyperplastic polyps to be left in situ and surveillance intervals to be determined without the need for histopathology. Although accurate in specialist practice the performance of narrow band imaging (NBI), colonoscopy in routine clinical practice is poorly understood.

Methods

NBI-assisted optical diagnosis was compared with reference standard histopathological findings in a prospective, blinded study, which recruited adults undergoing routine colonoscopy in six general hospitals in the UK. Participating colonoscopists (N=28) were trained using the NBI International Colorectal Endoscopic (NICE) classification (relating to colour, vessel structure and surface pattern). By comparing the optical and histological findings in patients with only small polyps, test sensitivity was determined at the patient level using two thresholds: presence of adenoma and need for surveillance. Accuracy of identifying adenomatous polyps <10 mm was compared at the polyp level using hierarchical models, allowing determinants of accuracy to be explored.

Findings

Of 1688 patients recruited, 722 (42.8%) had polyps <10 mm with 567 (78.5%) having only polyps <10 mm. Test sensitivity (presence of adenoma, N=499 patients) by NBI optical diagnosis was 83.4% (95% CI 79.6% to 86.9%), significantly less than the 95% sensitivity (p<0.001) this study was powered to detect. Test sensitivity (need for surveillance) was 73.0% (95% CI 66.5% to 79.9%). Analysed at the polyp level, test sensitivity (presence of adenoma, N=1620 polyps) was 76.1% (95% CI 72.8% to 79.1%). In fully adjusted analyses, test sensitivity was 99.4% (95% CI 98.2% to 99.8%) if two or more NICE adenoma characteristics were identified. Neither colonoscopist expertise, confidence in diagnosis nor use of high definition colonoscopy independently improved test accuracy.

Interpretation

This large multicentre study demonstrates that NBI optical diagnosis cannot currently be recommended for application in routine clinical practice. Further work is required to evaluate whether variation in test accuracy is related to polyp characteristics or colonoscopist training.

Trial registration number

The study was registered with clinicaltrials.gov (NCT01603927).

Affiliations

[1 ]Department of Gastroenterology, South Tyneside NHS Foundation Trust , South Shields, UK

[2 ]School of Medicine, Pharmacy and Health, Durham University , Durham, UK

[3 ]Northern Region Endoscopy Group, UK

[4 ]St Mark's Hospital and Academic Institute, London North West Healthcare NHS Trust, Imperial College London , London, UK

[5 ]Durham Clinical Trials Unit, School of Medicine Pharmacy & Health, Durham University , Stockton-on-Tees, UK

[6 ]Department of Gastroenterology, North Tees & Hartlepool NHS Foundation Trust , Stockton-on-Tees, UK

[7 ]Translational Gastroenterology Unit, John Radcliffe Hospital, University of Oxford , Oxford, UK

[8 ]Department of Gastroenterology, Northumbria Healthcare NHS Foundation Trust , Newcastle upon Tyne, UK

[9 ]Department of Gastroenterology, North Cumbria University Hospitals NHS Trust , Carlisle, UK

[10 ]Department of Gastroenterology, South Tees Hospitals NHS Foundation Trust , Middlesborough, UK

[11 ]Department of Gastroenterology, County Durham & Darlington NHS Foundation Trust , Darlington, UK

[12 ]Warwick Medical School, University of Warwick , Coventry, UK

Author notes

[Correspondence to ] Professor Colin J Rees, Department of Gastroenterology, South Tyneside District Hospital, South Shields NE34 0PL, UK; Colin.Rees@ 123456stft.nhs.uk

Journal

Journal ID (nlm-ta): Gut

Journal ID (iso-abbrev): Gut

Journal ID (hwp): gutjnl

Journal ID (publisher-id): gut

Title: Gut

Publisher: BMJ Publishing Group (BMA House, Tavistock Square, London, WC1H 9JR )

ISSN (Print): 0017-5749

ISSN (Electronic): 1468-3288

Publication date (Print): May 2017

Publication date (Electronic): 19 April 2016

Volume: 66

Issue: 5

Pages: 887-895

Publisher ID: gutjnl-2015-310584

DOI: 10.1136/gutjnl-2015-310584

PMC ID: 5531217

PubMed ID: 27196576

Other contributors: Laura Neilson (Collab), Adil Ahmed (Collab), Roisin Bevan (Collab), Mike Bradburn (Collab), Faheem Butt (Collab), Andrew Douglass (Collab), Vikki Edge (Collab), John Greenaway (Collab), Wendy Gregory (Collab), John Hancock (Collab), Lindsay Hurst (Collab), Babur Javaid (Collab), Diamond Joy (Collab), Deepak Kejariwal (Collab), Susan McConnell (Collab), Jestina Miles (Collab), Sarah Mills (Collab), David Oliver (Collab), Simon Panter (Collab), Francisco Porras-Perez (Collab), John Silcock (Collab), Joanne Topping (Collab), Christopher Wells (Collab), Jennifer Wilkinson (Collab), Catherine Frost (Collab), Greg Rubin (Collab), Janice Mulley (Collab), Yan Yiannakou (Collab), Stephen Attwood (Collab), Mike Bramble (Collab), Adetayo Kasim (Collab)

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License:

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Product

Categories

Subject: 1506

Subject: Endoscopy

Series title: Original article

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