Endoscopic Prediction of Tumor Invasion Depth in Early Gastric Signet Ring Cell Carcinoma

Introduction: Signet ring cell carcinoma (SRC) is a poorly differentiated cancer of the stomach. Recent studies imply that early gastric SRC can be well managed by endoscopic resection. Unfortunately, unlike differentiated cancers, the endoscopic features of early gastric SRC have not been well studied. This study evaluated the endoscopic features of early gastric SRC, as well as the risk factors for submucosal (SM) invasion. Method: The medical records of patients from 7 tertiary hospitals (Daejeon and Chungcheong province) were reviewed to examine endoscopic findings and clinical data. These patients underwent surgery or endoscopic resection between January 2011 and December 2016 and were divided into 2 groups (derivation group and validation group) in order to develop and validate an endoscopic scoring system for SM invasion. Results: In total, 331 patients (129 in the derivation group and 202 in the validation group) were enrolled in this study. In the derivation group, the risk factors for SM invasion, namely, fold convergence, nodular mucosal change, and deep depression, were identified by logistic regression analysis (ORs 3.4, 5.9, and 6.0, p < 0.05). A depth-prediction score was created by assigning 1 point for fold convergence and 2 points for other factors. When validation lesions of 0.5 point or more were diagnosed as SM invasion, the sensitivity and specificity were 76.8–78.6% and 61.6–74.7% respectively. Conclusion: Fold convergence, nodular mucosal change, and deep depression are risk factors for SM invasion in early gastric SRC. Our depth-prediction scoring system may be useful for differentiating SM cancers.