A New Classification of Narrow Band Imaging Magnification Endoscopy (NBI-ME) for Early Gastric Neoplasms (EGN) Before Endoscopic Submucosal Resection (ESD)

Abstract

Background: Some studies suggest that NBI-ME enhances endoscopic diagnosis of eGN compared to white light (WL). However, most NBI-ME classifications are too cumbersome for clinical use. Aims: To assess the utility of a simplified NBI-ME classification system for predicting the histology and endoscopic margins of eGN. Methods: 51 pts with eGN without ulceration were examined using a 80X magnifying gastroscope (GIF-Q240Z) and Evis-Lucera 260 processor (Olympus, Tokyo, Japan) using both WL and NBI-ME, before ESD. Gastric pit patterns, capillary networks, and tumor demarcation lines were carefully observed in 58 lesions: 44 well differentiated cancer (WD), 7 poorly differentiated cancers (PD), 7 dysplasia (DY). Gastric pit patterns: tubular, distorted, mixed (tubular dominant or distorted dominant), unclassified, and normal. Vascular patterns: capillary network pattern (CNP), abnormal tumor vessels (ATV), mixed, and normal. Demarcation lines: well demarcated, no demarcation, and equivocal. Endoscopic imaging quality score: 3- NBI-ME better than WL; 2- NBI-ME equal to WL; 1- WL better than NBI-ME. To assess its clinical utility, the pathologic complete resection (CR) rate of pts who had ESD using NBI-ME was compared with those who had ESD using WL. The pathologist was blinded to the imaging modality. Results: Pit patterns: WF: tubular pattern (6.8%), distorted (25%), mixed tubular dominant (36.3%) and mixed distorted dominant (27.3%) and unclassified (4.5%). PD: distorted (57.1%), mixed tubular dominant (14.2%) and mixed distorted dominant (28.5%). DY: tubular pattern (42.8%), distorted (28.5%), mixed tubular dominant (14.3%) and normal (14.3%). Vascular patterns: WD: CNP (2.2%), abnormal tumor vessels (81.8%), and mixed (9%), and normal (6.8%). PD: CNP (14.3%), abnormal tumor vessels (85.7%), and mixed (0%), and normal (0%). DY: CNP (28.6%), ATV (57.1%), and normal (14.2%). Demarcation lines: WD: well demarcated: (77.2%), not demarcated (15.9%), equivocal (6.8%). PD: well demarcated (28.5%), not demarcated (42.8%), equivocal (28.5%). DY: well demarcated (85.7%), not demarcated (14.2%), equivocal (0). The pathologic CR rate was 84.3% (177/210) using WL and 95.9% (55/58) using NBI-ME. The image quality score of NBI-ME was 2.89 ± 0.3. Conclusions: 1. most WD (88%) and PD (86%) cancers have abnormal tumor vessels, 2. Dysplastic lesions (86%) and WD cancers (77%), but not PD cancers, generally have endoscopically visible demarcation lines, 3. a tubular pits pattern suggests dysplasia, whereas a distorted pattern suggests PD. The ESD pathologic complete resection rate is marginally improved (10%) when using this simplified NBI-ME classification system.