Retrospective Assessment of the Diagnostic Accuracy of the Depth of Invasion by Narrow Band Imaging Magnifying Endoscopy in Patients with Superficial Esophageal Squamous Cell Carcinoma

Treatment strategies for superficial esophageal squamous cell carcinoma (S-ESCC) are determined mainly on the basis of the depth of invasion. We retrospectively studied the accuracy of the depth of tumor invasion, comprehensively assessed using the Japan Esophageal Society (JES) classification. The study group comprised 256 patients who underwent narrow band imaging (NBI) magnifying endoscopy, and endoscopic submucosal dissection for S-ESCC. The depth of invasion of S-ESCC was classified into three groups: EP/LPM, MM/SM1, and SM2. The following variables were studied retrospectively: (1) the diagnostic accuracy of non-magnifying white-light endoscopy, (2) the diagnostic accuracy of type B vessels, (3) the diagnostic accuracy of avascular area (AVA), (4) the diagnostic accuracy of the JES classification, and (5) the diagnostic accuracy of comprehensive diagnosis. The depth of invasion was assessed by white-light non-magnifying endoscopy, followed by NBI magnifying endoscopy. The positive predictive value (PPV) of white-light non-magnifying endoscopy was 86% for EP/LPM, 53% MM/SM1, and 74% for SM2. The PPV of the diagnosis of type B vessels was 93% for EP/LPM, 62% for MM/SM1, and 74% for SM2. The PPV of the AVA diagnosis was 73% for EP/LPM, 89% for MM/SM1, and 100% for SM2. The PPV of diagnosis according to the JES classification was 93% for EP/LPM, 65% for MM/SM1, and 77% for SM2. The PPV of the comprehensive diagnosis was 94% for EP/LPM, 63%, for MM/SM1, and 75% for SM2. The additional use of NBI magnifying endoscopy can enhance the diagnostic accuracy of the depth of invasion in patients with S-ESCC.