New magnifying endoscopic classification for superficial esophageal squamous cell carcinoma

AIM: To assess the accuracy of a new magnifying endoscopy (ME) classification for predicting depth of invasion of superficial esophageal squamous cell carcinoma (SESCC). METHODS: This study included a total of 70 lesions in 69 patients with SESCC who underwent ME with narrow-band imaging (ME-NBI) before resection from August 2010 to July 2016. Accuracy of ME-NBI for predicting depth of invasion of SESCC was analyzed by using a new ME classification proposed by the Japan Esophageal Society (JES), and interobserver agreement was assessed. RESULTS: Overall accuracy of ME-NBI for estimating depth of invasion of SESCC was 78.6%. Sensitivity and specificity of type B1 for tumors limited to the epithelial layer (m1) or invading into the lamina propria (m2) were 71.4% and 100%, respectively. Sensitivity and specificity of type B2 for tumors invading into the muscularis mucosa (m3) or superficial submucosa (≤ 200 μm, sm1) were 94.4% and 73.1%, respectively, while those of type B3 for tumors invading into the deep submucosa (> 200 μm, sm2) were 75.0% and 97.8%, respectively. Interobserver agreement was excellent (κ = 0.86, 95%CI: 0.76-0.95). CONCLUSION: The recently developed JES ME classification is useful for predicting depth of invasion of SESCC, with reliable interobserver agreement.