Reducing chronic infections from the bacterium Helicobacter pylori would be a key strategy for preventing stomach cancer, according to research published today in The Lancet Public Health.
Gastric (stomach) cancer is the second leading cause of cancer death globally, responsible for around 770,000 deaths in 2020, with China accounting for over half (478,000) of the global disease burden. One of the most important and preventable causes of gastric cancer is infection by the bacterium Helicobacter pylori (H. pylori), which attacks the stomach lining. Based on evidence mainly from Western populations, the World Health Organization estimated that H. pylori was responsible for 0.8 million new cases of gastric cancer globally in 2018.
Previous studies have demonstrated a clear link between H. pylori infection and non-cardia gastric cancer (NCGC): cancer in the main area of the stomach. However, the estimated risk from infection varies considerably across these studies, depending on the study design and type of assay used. Moreover, there was conflicting evidence on whether H. pylori also causes cardia gastric cancer (CGC), which occurs at the top of the stomach where it joins the oesophagus. CGC accounts for about a third of gastric cancer cases globally.
The CKB study recruited over half a million adults from ten diverse geographical regions across China between 2004 and 2008. The study participants completed a baseline survey, then their health outcomes were tracked through electronic linkage to death and cancer registries, and national health insurance databases. H. pylori infection was determined using a highly-sensitive immunoblot assay on the stored blood samples taken during the baseline survey. The assay tests for the presence of seven diagnostic antibodies which bind to H. pylori proteins. This is the first time that immunoblot assays have been used on a large scale to assess H. pylori infection in China.
Our study showed that H. pylori infection was associated with a six-fold higher risk of NCGC and a three-fold higher risk of CGC. These relative risk estimates were twice as strong as those estimated in Chinese adults by previous studies that used less sensitive assays. - Dr Ling Yang, senior epidemiologist in Oxford Population Health, who led the investigation
These updated estimates of the risk and burden of gastric cancer due to H. pylori infection will help refine global disease burden estimates and help policy makers develop and implement suitable strategies for cancer prevention locally and globally. Population-level H. pylori mass screening and eradication should be considered as a key strategy for gastric cancer prevention in China and high-risk settings globally. - Professor Zhengming Chen, principal investigator in the UK for the China Kadoorie Biobank and a senior author of the paper
The work was mainly funded by Cancer Research UK and also involved collaborators from China and the International Agency for Research on Cancer. Last year Cancer Research UK also awarded a five-year programme grant to CKB to comprehensively investigate the roles of 19 different pathogens in cancer.
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