Mo1519 Endoscopic Prediction of Tumor Invasion Depth in Early Gastric Cancer

Abstract

Although conventional endoscopy is a good diagnostic tool of evaluation of tumor depth (T staging) in early gastric cancer (EGC), its accuracy has not been determined and no consensus has been reached regarding standard endoscopic criteria. We aimed to evaluate the diagnostic accuracy of endoscopic T staging and to identify characteristic endoscopic features for mucosal (T1m) and submucosal (T1sm) tumors. A consecutive 2105 patients with EGC underwent either surgical (n=1624) or endoscopic resection (n=481) were enrolled. Endoscopic staging was performed retrospectively by consensus between two endoscopists, which was based on the characteristic endoscopic criteria of T1m (smooth surface protrusion or depression, slight marginal elevation, smooth tapering of converging folds) and those for T1sm (irregular surface, marked marginal elevation, and clubbing/abrupt cutting/fusion of converging folds). The endoscopic staging was compared with the pathological staging of the resected specimen. Overall accuracy of endoscopic staging was 78.0% (1642/2105) (95% confidence interval, 76.2%-79.7%). The sensitivity, specificity, and positive and negative predictive values of endoscopic staging for T1m were 85.5%, 73.9%, 82.0%, and 78.5%, whereas those for T1sm were 72.6%, 81.9%, 71.9%, and 82.4%, respectively. Significant associations were observed between endoscopic prediction criteria for mucosal and submucosal cancer and a correct diagnosis. Conventional endoscopy was found to provided reliable accuracy for T staging in early gastric cancer, and thus it may be an effective method for assessing penetration depth. A detailed endoscopic evaluation regarding tumor base, margin, and converging folds may provide useful information to determine tumor depth and to select the optimal therapeutic strategy, particularly for endoscopic resection.