Clinicopathological features of Epstein-Barr virus-associated gastric carcinoma: A systematic review and meta-analysis.

PURPOSE: The purpose of this meta-analysis was to explore the clinicopathological characteristics of Epstein-Barr virus (EBV)-associated gastric carcinoma (AGC) based on qualified studies. METHODS: PubMed, Cochrane and Embase databases updated to November 2017 were searched by the index words to identify relevant studies, including qualified randomized controlled trials, cohort studies or case-control studies. Studies were also identified by tracking reference lists. The meta-analysis included relative risks (RR), mean difference (MD) along with 95% confidence interval (95% CI) to analyze the main outcomes. RESULTS: A total of 35 studies were included in this meta-analysis with 7540 cases and 950 Epstein-Barr virus associated gastric cancer (EBVaGC) cases. The results indicated the EBV infection rate was significantly higher in males than in females (OR, 0.42; 95%CI 0.35-0.52), and the EBV infection rate was significantly higher in the diffuse type than in intestinal type (OR, 1.56; 95%CI 1.24-1.97). Besides, there was no marked association of EBV infection rate with lymph node metastasis (OR, 0.73; 95%CI 0.41-1.29), age (OR, 0.78; 95%CI 0.61-1.00) and pathologic tumor stage (OR, 1.11; 95%CI 0.90-1.38). The results of funnel plot, Begg's and Mazumdar's rank test, and Egger's test all showed no significant publication bias. CONCLUSIONS: In this meta-analysis, EBV infection rate was significantly higher in males and in diffuse cancer type. However, there was no marked association with lymph node metastasis, age and pathologic tumor stage. Thus, EBV-positive gastric cancer has distinct clinicopathological features.