Reliability of Japan Narrow-Band Imaging Expert Team Classification for the Diagnosis of Colorectal Neoplasms: A Pilot Study.

INTRODUCTION: Magnifying narrow-band imaging (NBI) is a beneficial modality for the prediction of histology in colonoscopy. The Japan NBI Expert Team (JNET) classification has been established based on the results of online surveys of the diagnostic accuracy of histological features. However, the reliability of the JNET classification has not been examined. The aim of this study was to evaluate the degree of interobserver agreement for JNET classification among endoscopists when evaluating colonic lesions. METHODS: We analyzed a total of 246 colonic lesions in this interpretation test. Each lesion image was subsequently reviewed by 3 experienced endoscopists and then classified based on 4 established JNET categories and indeterminate categories between fixed categories. The primary endpoint was the interobserver agreement rate for evaluation of endoscopic findings using the JNET classification. RESULTS: The complete concordance (defined as 3 out of 3 observer agreement) rate was 73% (179/246), while the partial concordance (defined as 2 out of 3 observer agreement) rate was 26% (64/246). Therefore, concordance of at least 2 out of 3 was achieved in 99% of all the lesions and disagreement of the 3 endoscopists was found in only 1% (3/246). Fleiss's kappa coefficient (κ) was 0.72 for all cases, which represents moderate interobserver agreement for observers. DISCUSSION/CONCLUSION: Our study highlights the reliability of the JNET classification for colonic neoplastic lesions among experienced endoscopists and demonstrates acceptable interobserver agreement. Further studies validating the clinical applicability of JNET classification are required among endoscopists with a variety of expertise in several clinical settings.

Comparative evaluation of new and conventional classifications of magnifying endoscopy with narrow band imaging for invasion depth of superficial esophageal squamous cell carcinoma.

A new classification of magnifying endoscopy with narrow band imaging (ME-NBI) for diagnosing and staging superficial esophageal squamous cell carcinoma (SESCC) was proposed by the Japan Esophageal Society in 2011. This study aimed to compare the new classification with the conventional classifications (Inoue's classification and Arima's classification). This was a prospective analysis of data from a single cancer center involving 151 consecutive patients with 156 SESCCs that were endoscopically or surgically resected. Initially, only ME-NBI images were selected and reviewed independently by three experienced endoscopists. White light imaging (WLI) was then evaluated separately after an interval. The diagnostic performance of each classification and interobserver agreement were assessed, and the WLI findings that affect the diagnosis by the new classification were identified. The specificity for classifying invasive depth as epithelium (EP)/lamina propria mucosae (LPM) confined was higher with the new classification than with Inoue's classification (0.512 vs. 0.349; P = 0.02) and Arima's classification (0.512 vs. 0.279; P < 0.01). However, the sensitivity was lower (0.902 vs. 1.000; P < 0.01) compared with Arima's classification. The concordance rates of three evaluators (κ values) were 0.52 for the new classification, 0.50 for Inoue's classification, and 0.23 for Arima's classification. On multivariate analysis, thickness on WLI independently affected the accuracy of diagnosis with the new classification (OR 3.23; 95%CI, 1.30-8.03). The new classification is superior to conventional classifications with respect to specificity for diagnosing SESCC with depth EP/LPM. Thickness on WLI was a factor negatively affecting the diagnostic performance of the new classification.