Su1980 How to Refine Treatment Strategy in Patients With Gastric Subepithelial Tumor

Abstract

Background: Lymphoepithelioma-like gastric carcinoma (LELC), which is characterized by a dense infiltration of lymphocytes in the tumor stroma, is associated with EBV infection in more than 80% of cases. There have been few studies on the clinicopathologic characteristics and prognosis of EBV-negative LELC compared to EBV-positive LELC. In addition, it remains controversial whether EBV infection itself plays a role in determining the prognosis of LELC. Methods: From 1994 to 2011, 124 EBV-positive and 21 EBV-negative curatively resected LELCs were identified. Their clinicopathologic characteristics and prognosis were compared. To identify independent risk factors for survival, multivariate analyses were performed. Results: Patients with EBV-positive LELC were more frequently associated with young age, male gender, lower T stage, and lower AJCC stage than those of EBV-negative LELC. In Kaplan-Meier curves, patients with EBV-positive LELC showed more favorable overall and recurrence free survival than those of EBV-negative LELC (p=0.011, p=0.004, respectively). In Cox proportional hazard model, older age (Hazard ratio (HR) 1.102, 97.5% CI 1.010-1.202), EBV-negative status (HR 15.958, 97.5% CI 2.412-105.582) and stage IIIIV (HR 8.1, 97.5% CI 1.119-58.634) were identified as independent predictors of overall survival in patients with LELC. Conclusion: EBV-negative LELC showed distinct features compared to their EBV-positive counterpart. EBV Infection might serves as an independent predictor of survival in patients with LELC. Further studies are required to confirm our results and to identify underlying mechanism of this finding.