Unified magnifying endoscopic classification for esophageal, gastric and colonic lesions: a feasibility pilot study

Abstract

Background and study aims Image-enhanced magnifying endoscopy allows optimization of the detection and diagnosis of lesions found in the gastrointestinal tract. Current organ-specific classifications are well-accepted by specialized endoscopists but may pose confusion for general gastroenterologists. To address this, our group proposed the Unified Magnifying Endoscopic Classification (UMEC) which can be applied either in esophagus, stomach, or colon. The aim of this study was to evaluate the diagnostic performance and clinical applicability of UMEC. Patients and methods A single-center, feasibility pilot study was conducted. Two endoscopists with experience in magnifying narrow band imaging (NBI), blinded to white-light and non-magnifying NBI findings as well as histopathological diagnosis, independently reviewed and diagnosed all images based on UMEC. In brief, UMEC is divided into three categories: non-neoplasia, intramucosal neoplasia, and deep submucosal invasive cancer. The diagnostic performance of UMEC was assessed while using the gold standard histopathology as a reference. Results A total of 303 gastrointestinal lesions (88 esophageal squamous lesions, 90 gastric lesions, 125 colonic lesions) were assessed. The overall accuracy for both endoscopists in the diagnosis of esophageal squamous cell cancer, gastric cancer, and colorectal cancer were 84.7 %, 89.5 %, and 83.2 %, respectively. The interobserver agreement for each organ, Kappa statistics of 0.51, 0.73, and 0.63, was good. Conclusions UMEC appears to be a simple and practically acceptable classification, particularly to general gastroenterologists, due to its good diagnostic accuracy, and deserves further evaluation in future studies.

Fig. 1

UMEC for esophagus (E-UMEC). a E-UMEC 1 are considered non-neoplastic, b E-UMEC 2A as inflammation and low-grade intramucosal neoplasia, c UMEC 2B as high-grade intramucosal neoplasia and intramucosal cancer, and d E-UMEC 3 as invasive cancer.

Fig. 2

UMEC for stomach (S-UMEC). a S-UMEC 1/2A are considered as non-cancer and b S-UMEC 2B/3 as cancer.

Fig. 3

UMEC for colon (C-UMEC). a C-UMEC 1 are considered as hyperplastic polyp and sessile serrated polyp, b C-UMEC 2A as low-grade intramucosal neoplasia, c C-UMEC 2B as non-invasive, high-grade neoplasia/intramucosal carcinoma/carcinoma in situ (Tis), and superficial submucosal invasive carcinoma (SM-s: T1a; < 1,000 µm), and d C-UMEC 3 as deep submucosal invasive carcinoma (SM-d: T1b; ≥ 1,000 µm).