Zooming in on Barrett oesophagus using narrow-band imaging: an international observer agreement study.

BACKGROUND: Several classifications of mucosal morphology have been proposed in Barrett oesophagus using narrow-band imaging (NBI). We evaluated a simplified classification in which only the regularity of mucosal and vascular patterns were evaluated. AIM: To assess the inter and intraobserver agreement and the correlation with histology of a simplified NBI classification of mucosal morphology in Barrett oesophagus combining the experience of two referral centres. METHODS: Two hundred NBI images [57 high-grade intraepithelial neoplasia (HGIN)/early cancer (EC)] were evaluated twice by four NBI-experienced and four nonexperienced endoscopists in the field of NBI. Endoscopists assessed each image for: quality, suspicion for dysplasia, and regularity of mucosal and vascular patterns. Observer agreement was assessed using kappa statistics. RESULTS: Overall interobserver agreement for the items evaluated was 'moderate' and varied between 0.42 and 0.44. Overall intraobserver agreement was 'moderate' to 'substantial' (kappa 0.60-0.62). There were no significant differences in agreement between expert and nonexpert endoscopists. Endoscopist correctly identified 71% of the images containing HGIN/EC. Of the areas without HGIN/EC, 68% were correctly identified as not suspicious. Again, there were no significant differences between experts and nonexperts. CONCLUSION: Our proposed, simplified classification for Barrett mucosal morphology has a moderate interobserver and a moderate to substantial intraobserver agreement. The lack of differences in agreements between expert and nonexpert endoscopists suggests a short learning curve. The disappointing rate for correctly indentifying HGIN/EC, questions, however, whether detailed inspection of Barrett oesophagus with NBI can replace histological sampling.

Recognition of surface mucosal and vascular patterns of colon polyps by using narrow-band imaging: interobserver and intraobserver agreement and prediction of polyp histology.

BACKGROUND: The 2 main types of colon polyps are adenomas and hyperplastic. Pit patterns on the surface of polyps have been described by using magnification chromoendoscopy, which can help differentiate between polyp types. Narrow band imaging (NBI) is a novel technology that enhances the visualization of surface mucosal and vascular patterns on the polyp surface. Earlier we described, in a pilot study, patterns seen on the polyp surface with NBI that can help differentiate between adenomas and hyperplastic polyps with a high degree of accuracy. OBJECTIVE: The aim of this study was to evaluate the interobserver and intraobserver agreement (among endoscopists) for the NBI surface mucosal and vascular patterns and prediction of polyp histology and the accuracy of the investigators to predict polyp histology based on these patterns. SETTING: Kansas City Veterans Affairs Medical Center. METHODS: NBI images of the polyp surface mucosal and vascular patterns obtained in our pilot trial were retrieved. A teaching set of 20 images was selected to educate and demonstrate the polyp patterns to 4 endoscopists. Subsequently, the test set of images was evaluated by the 4 endoscopists for quality, polyp pattern, and prediction of polyp type. Interobserver agreement (k value) was calculated among the 4 assessors for the polyp patterns and predicted histology. By using the final histology as the criterion standard, the accuracy of polyp-type prediction was calculated for each assessor. After a period of 2 months, all polyp images were reevaluated by the assessors (as before), and all findings were recorded in a similar fashion. These results were used for calculation of intraobserver agreement (k value) and the accuracy of the assessors in predicting polyp type. RESULTS: Photographs of 65 polyps were included in the test set and were evaluated by the 4 assessors. Thirty-eight polyps were adenomatous, and 27 were hyperplastic. The kappa value for the interobserver agreement for polyp surface pattern was 0.57 (moderate) and for prediction of polyp type was 0.63 (substantial). The kappa value for the intraobserver agreement of the 4 assessors for the surface patterns was 0.70, 0.65, 0.60, and 0.79, and for the prediction of polyp type was 0.87, 0.71, 0.61, 0.81. The accuracy to predict polyp type ranged from 80% to 86% for the 4 assessors in the first reading and from 85% to 91% in the second reading, with every assessor showing an improvement in accuracy in the second reading. LIMITATIONS: A single-center study, with a limited number of polyps. CONCLUSIONS: This initial evaluation showed that the NBI polyp patterns described in our pilot study are reproducible, easy to learn, reasonably accurate, and have the potential for use in daily clinical practice for the real-time differentiation of colon polyps.

Barrett's esophagus and esophageal adenocarcinoma in adults: long-term GERD or something else?

Esophageal adenocarcinoma (EAC) is a highly lethal tumor and is currently the most rapidly rising incidence cancer in the Western world. Numerous risk factors in the development of Barrett's esophagus (BE) (a precursor of EAC) and EAC itself have been identified and are likely multifactorial. Gastroesophageal reflux disease (GERD) is a significant risk factor for BE and EAC; however, only a minority of patients with chronic GERD actually develop BE. Thus, other risk factors that modulate reflux-related inflammatory and neoplastic effects on esophageal epithelium must exist. Epidemiologic data have prompted initiation of chemopreventive trials using aspirin and proton pump inhibitors in the treatment of BE and EAC. Further research should also clarify the role of risk factors such as ethnicity and obesity in BE and EAC development and progression. Identification of prognostic factors would allow better risk stratification of patients and ultimately impact the rising incidence of EAC.