The relationship between infection with cagA-positive strains of Helicobacter pylori and gastric cancer, over and above H. pylori infection alone, is unclear.
In this study, investigators from Canada and China estimated the risk for gastric cancer associated with cagA seropositivity. They also identified any sources of heterogeneity between studies.
The team performed a meta-analysis of case-control studies with age- and sex-matched controls. They included studies which provided raw data on the infection rates with H. pylori and cagA strains of H. pylori as detected by serology or polymerase chain reaction DNA.
A comprehensive literature search identified 16 qualified studies with 2284 cases and 2770 controls.
|Gastric cancer at the cardia is not associated with H. pylori infection.|
They investigators found that H. pylori and cagA seropositivity significantly increased the risk for gastric cancer by 2.28- and 2.87-fold, respectively.
Among the infected populations, cagA -positive strains further increased the risk for gastric cancer by 1.64-fold overall, and by 2.01-fold for noncardia gastric cancer.
The team determined that gastric cancer at the cardia is not associated with H. pylori infection or cagA -positive strains of H. pylori.
Dr Jia Qing Huang's team concluded, "Infection with cagA -positive strains of H. pylori increases the risk for gastric cancer over the risk associated with H. pylori infection alone".
"Searching for cagA status over H. pylori infection may confer additional benefit in identifying populations at greater risk for gastric cancer."