Is It a Protective Factor of Helicobacter pylori Infection in Overall Survival of All Gastric Cancer? Evidence from Meta-Analysis.

Purpose - We aimed to assess whether Helicobacter pylori infection influences prognosis in gastric cancer patients (GC). Methods - We systematically searched MEDLINE, PubMed, EBSCO, EMBASE, and the Cochrane Library (CENTRAL) Register from inception to June 1, 2017. Overall survival (mean OS) or disease-free survival (mean DFS) in GC patients were calculated using the hazard ratio (HR) and 95% confidence intervals (95% CIs). Results - In total, 19 articles with 4,321 GC patients were enrolled. Helicobacter pylori infection is associated with longer OS (HR 0.73; 95% CI 0.60-0.89; P < 0.001) and DFS (HR 0.75; 95% CI 0.53-1.07; P = 0.002) in GC patients overall. For our subgroup analysis, the pooled HRs and 95% CIs were as follows: China (OS: HR 0.95; 95% CI 0.63-1.42; P = 0.804 and DFS: HR 0.88; 95% CI 0.50-1.56; P = 0.658), Europe (OS: HR 0.69; 95% CI 0.52-0.92; P = 0.010 and DFS: HR 0.62; 95% CI 0.32-1.17; P = 0.141), United States (OS: HR 0.77: 95% CI 0.56-1.06; P = 0.105), Korea (OS: HR 0.45; 95% CI 0.27-0.75; P = 0.002 and DFS: HR 0.45; 95% CI 0.24-0.83, P = 0.011), and Turkey (OS: HR 0.94; 95% CI 0.52-1.70; P = 0.839 and DFS: HR 0.95; 95% CI 0.53-1.71, P = 0.864). Moreover, for R0 or M0 patients, H. pylori infection is associated with better OS and DFS (P all values < 0.05). Conclusions - Helicobacter pylori infection has a better prognosis in GC patients from Korea and Europe. Helicobacter pylori infection has no association with prognosis for China, the United States, or Turkey. Also, H. pylori infection has a better prognosis in R0 resection or M0 GC patients.