Diagnostic Accuracy and Interobserver Agreement in Predicting the Submucosal Invasion of Colorectal Tumors Using Gross Findings, Pit Patterns, and Microvasculatures

BACKGROUND/AIMS Depth of invasion is one of the most important factors for establishing treatment strategy for colorectal tumors. METHODS Three blinded experts reviewed electronic photos and video clips of 33 early colorectal cancer-like lesions. They estimated the depth of invasion based on conventional white light endoscopy (CWE), magnifying chromoendoscopy (MCE), and magnifying narrow band imaging endoscopy (MNE). RESULTS The lesions included nine mucosal low-grade neoplasias, 16 mucosal high grade neoplasias, and eight carcinomas with invasion to the submucosal layer or beyond. The diagnostic accuracy for submucosal invasion by CWE ranged from 67% to 82%, while those by MCE and MNE ranged from 85% to 88% and 85% to 88%, respectively. The diagnostic accuracy significantly differed between CWE and MCE (p=0.034) and between CWE and MNE (p=0.039). The kappa values for CWE, MCE, and MNE among the endoscopists were 0.564, 0.673, and 0.673, respectively. CONCLUSIONS The estimation of submucosal invasion for early colorectal cancer-like lesions based on MCE or MNE is more accurate than CWE. MCE and MNE were demonstrated to have substantial agreement for predicting submucosal invasion.