Efficacy of Magnifying Narrow Band Imaging for Delineating Horizontal Margins of Early Gastric Cancer

Background/Aims: The aim of this study was to evaluate the diagnostic accuracy of magnifying narrow-band imaging (M-NBI) with histopathological confirmation in identifying the demarcation line (DL) of early gastric cancer (EGC). Methods: EGCs resected by endoscopic submucosal dissection after identifying the DL using M-NBI following histopathological confirmation were included. After determining the DL for the entire EGC lesion using M-NBI, at least 4 biopsies were taken from non-cancerous tissues outside the EGC lesion for histopathological confirmation. Results: A total of 330 EGCs were analyzed in this study. The rate of biopsy-negative and negative horizontal margin were 96.7% (319/330) and 97.9% (323/330) in EGC respectively. Tumors larger than 20 mm showed a higher risk for showing remnant cancer cells on biopsies taken outside the DL. Risk factors for a positive horizontal resection margin were tumor size > 20 mm and moderately or poorly differentiated adenocarcinomas. Conclusion: The assessment of demarcation of EGC using M-NBI was excellent in well-differentiated (WD) adenocarcinoma and lesions below 20 mm in size. However, histopathological confirmation is needed to assess the demarcation of non-WD adenocarcinomas and EGC over 20 mm in size.