Narrow band imaging to detect residual or recurrent neoplastic tissue during surveillance endoscopy

Optical Technologies for Endoscopic Real-Time Histologic Assessment of Colorectal Polyps: A Meta-Analysis

OBJECTIVES

Accurate, real-time, endoscopic risk stratification of colorectal polyps would improve decision-making and optimize clinical efficiency. Technologies to manipulate endoscopic optical outputs can be used to predict polyp histology in vivo; however, it remains unclear how accuracy has progressed and whether it is sufficient for routine clinical implementation.

METHODS

A meta-analysis was conducted by searching MEDLINE, Embase, and the Cochrane Library. Studies were included if they prospectively deployed an endoscopic optical technology for real-time in vivo prediction of adenomatous colorectal polyps. Polyposis and inflammatory bowel diseases were excluded. Bayesian bivariate meta-analysis was performed, presenting 95% confidence intervals (CI).

RESULTS

One hundred two studies using optical technologies on 33,123 colorectal polyps were included. Digital chromoendoscopy differentiated neoplasia (adenoma and adenocarcinoma) from benign polyps with sensitivity of 92.2% (90.6%-93.9% CI) and specificity of 84.0% (81.5%-86.3% CI), with no difference between constituent technologies (narrow-band imaging, Fuji intelligent Chromo Endoscopy, iSCAN) or with only diminutive polyps. Dye chromoendoscopy had sensitivity of 92.7% (90.1%-94.9% CI) and specificity of 86.6% (82.9%-89.9% CI), similarly unchanged for diminutive polyps. Spectral analysis of autofluorescence had sensitivity of 94.4% (84.0%-99.1% CI) and specificity of 50.9% (13.2%-88.8% CI). Endomicroscopy had sensitivity of 93.6% (85.3%-98.3% CI) and specificity of 92.5% (81.8%-98.1% CI). Computer-aided diagnosis had sensitivity of 88.9% (74.2%-96.7% CI) and specificity of 80.4% (52.6%-95.7% CI). Prediction confidence and endoscopist experience alone did not significantly improve any technology. The only subgroup to demonstrate a negative predictive value for adenoma above 90% was digital chromoendoscopy, making high confidence predictions of diminutive recto-sigmoid polyps. Chronologic meta-analyses show a falling negative predictive value over time. A significant publication bias exists.

DISCUSSION

This novel approach to meta-analysis demonstrates that existing optical technologies are increasingly unlikely to allow safe "resect and discard" strategies and that step-change innovation may be required. A "diagnose and leave" strategy may be supported for diminutive recto-sigmoid polyps diagnosed with high confidence; however, limitations exist in the evidence base for this cohort.

Narrow band imaging and white light endoscopy in the characterization of a polypectomy scar: A single-blind observational study

AIM

To assess the incremental benefit of narrow band imaging (NBI) and white light endoscopy (WLE), randomizing the initial technique for the detection of residual neoplasia at the polypectomy scar after an endoscopic piecemeal mucosal resection (EPMR).

METHODS

We conducted an observational study in an academic center to assess the incremental benefit of NBI and WLE randomly applied 1:1 (NBI-WLE or WLE-NBI) in the follow-up of a post-EPMR scar by the same endoscopist.

RESULTS

A total of 112 EPMR scars were included. The median baseline polyp size was 20 mm (interquartile range: 14-30). At first review, NBI and WLE showed good sensitivity (85.0% vs 78.9%), specificity (77.1% vs 84.2%) and overall accuracy (80.0% vs 82.5%). NBI after WLE (WLE-NBI group) improved accuracy, but this difference was not statistically significant [area under the curve (AUC): 86.8% vs 81.6%, P = 0.15]. WLE after NBI (NBI-WLE group) did not improve accuracy (AUC: 81.4% vs 81.1%, P = 0.9). Overall, recurrence was found in 39/112 (34.8%) lesions.

CONCLUSION

Although no statistically significant differences were found between the two techniques at the first post-EPMR assessment, the use of NBI after WLE may improve residual neoplasia detection. Nevertheless, biopsy is still required in the first scar review.

Digital chromoendoscopy utilization in clinical practice: A survey of gastroenterologists in Connecticut

AIM: To use a survey to characterize and identify potential barriers to the use of digital chromoendoscopy (DC) by practicing gastroenterologists.

METHODS: An anonymous, internet-based survey was sent to gastroenterologists in Connecticut who were members of one of three national gastrointestinal organizations. The survey collected demographic information, frequency of DC use, types of procedures that the respondent performs, setting of practice (academic vs community), years out of training, amount of training in DC, desire to have DC training and perceived barriers to DC use. Responses were collected anonymously. The primary endpoint was the proportion of endoscopists utilizing DC. Associations between the various data collected were analyzed using χ² test.

RESULTS: One hundred and twenty-four gastroenterologists (48%) of 261 who received the online survey responded. Seventy-eight percent of surveyed gastroenterologists have used DC during the performance of upper endoscopy and 81% with lower endoscopy. DC was used in more than half of procedures by only 14% of gastroenterologists during upper endoscopy and 12% during lower endoscopy. Twenty-three percent (upper) and 21% (lower) used DC more than one quarter of the time. DC was used for 10% or less of endoscopies by 60% (upper) and 53% (lower) of respondents. Endoscopists reported lack of training as the leading deterrent to DC use with 36% reporting it as their primary deterrent. Eighty-nine percent of endoscopists never received formal training in DC. Lack of time (30% of respondents), lack of evidence (24%) and lack of reimbursement (10%) were additional deterrents. There were no differences in DC use relative to academic vs community practice setting or years out of training.

CONCLUSION: DC is used infrequently by most endoscopists, primarily due to a lack of training. Training opportunities should be expanded to meet the interest expressed by the majority of endoscopists.

British Society of Gastroenterology/Association of Coloproctologists of Great Britain and Ireland guidelines for the management of large non-pedunculated colorectal polyps

These guidelines provide an evidence-based framework for the management of patients with large non-pedunculated colorectal polyps (LNPCPs), in addition to identifying key performance indicators (KPIs) that permit the audit of quality outcomes. These are areas not previously covered by British Society of Gastroenterology (BSG) Guidelines.A National Institute of Health and Care Excellence (NICE) compliant BSG guideline development process was used throughout and the Appraisal of Guidelines for Research and Evaluation (AGREE II) tool was used to structure the guideline development process. A systematic review of literature was conducted for English language articles up to May 2014 concerning the assessment and management of LNPCPs. Quality of evaluated studies was assessed using the Scottish Intercollegiate Guidelines Network (SIGN) Methodology Checklist System. Proposed recommendation statements were evaluated by each member of the Guideline Development Group (GDG) on a scale from 1 (strongly agree) to 5 (strongly disagree) with >80% agreement required for consensus to be reached. Where consensus was not reached a modified Delphi process was used to re-evaluate and modify proposed statements until consensus was reached or the statement discarded. A round table meeting was subsequently held to finalise recommendations and to evaluate the strength of evidence discussed. The GRADE tool was used to assess the strength of evidence and strength of recommendation for finalised statements.KPIs, a training framework and potential research questions for the management of LNPCPs were also developed. It is hoped that these guidelines will improve the assessment and management of LNPCPs.

Diagnostic accuracy of probe-based confocal laser endomicroscopy and narrow band imaging in detection of dysplasia in duodenal polyps

GOALS

To estimate the accuracy of probe-based confocal laser endomicroscopy (pCLE) and narrow band imaging (NBI), individually and in combination, for classification of duodenal polyps.

BACKGROUND

Ex vivo pathologic diagnosis of duodenal polyps causes time delay, requiring separate procedures for diagnosis and therapy. It also involves small risk of pancreatitis in ampullary adenomas and can make subsequent endoscopic mucosal resection more difficult by "tacking down" mucosa. In vivo diagnosis with pCLE and NBI may avoid these complications and may guide immediate therapy.

STUDY

During high-definition white light endoscopy, 1 endoscopist (M.B.W.) performed NBI and then, pCLE of duodenal sites. Matched tissue sampling or endoscopic mucosal resection was performed. Confocal videos were recorded, de-identified, and reviewed by same endoscopist, blinded to histopathology, 1 month later. Confocal features of dysplasia in Barrett esophagus were applied for detection of duodenal dysplasia.

RESULTS

Of 65 sites from 36 participants, 24 lesions showed dysplasia, whereas 41 polyps and control sites were nondysplastic on histopathology, used as standard reference. The accuracy, sensitivity, and specificity of pCLE were 83%, 92%, and 78%, whereas that of NBI were 80%, 83%, and 78%, respectively. In subset of 49 lesions with similar pCLE and NBI diagnosis, the accuracy, sensitivity, and specificity, improved significantly and was found to be 92%, 95%, and 90%, respectively.

CONCLUSIONS

Our study suggests that pCLE has superior sensitivity as compared with NBI for detection of dysplasia in duodenal polyps. Combined accuracy of pCLE and NBI approaches that of ex vivo pathology, which may help in avoiding biopsy sampling.