Clinical and Histopathological Features of Early Gastric Cancer With Unclear Lateral Demarcation

Background: Magnifying-endoscopy with narrow band imaging (M-NBI) is useful to determine lateral demarcation of early gastric cancers, but determining the lateral demarcation is sometimes difficult. Features related to the unclear lateral demarcation remain unknown. We evaluated the clinical and histopathological features of early gastric cancers with unclear lateral demarcation by M-NBI. Methods This single-center retrospective cohort study analyzed early gastric cancer treated by endoscopic submucosal dissection (ESD) from January 2013 to August 2015. We evaluated clinicopathological and immunohistochemical features using anti-p53, -Ki-67, -MUC5AC, -MUC6, -MUC2, and -CD10 antibody staining. We compared the lateral demarcation between the demarcation clear (DC) and demarcation unclear (DU) lesions by using M-NBI. Results A total of 224 differentiated adenocarcinomas (DU group: 18 lesions; DC group: 206 lesions) were analyzed. The history of successful Helicobacter pylori eradication was significantly more frequent in the DU group (p = 0.001). We examined tissues of 72 lesions immunohistochemically, including 18 lesions in the DU group and 54 randomly selected lesions in the DC group. Non-neoplastic superficial epithelium is more frequently observed in the DU group (p = 0.0058). Additionally, the DU group showed a significantly higher expression of gastric phenotype marker (p = 0.023), lower p53 score (p = 0.0002), and lower Ki-67 labeling index (p = 0.0293). The non-neoplastic superficial epithelium and low p53 score were significant independent variables associated with unclear lateral demarcation by M-NBI in the multivariate analysis. Conclusions Non-neoplastic superficial epithelium and low p53 score were associated with the difficultly in determining lateral demarcation in early gastric cancers by M-NBI.