Study strengthens evidence of link between H. pylori and colorectal cancer

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By Sarah Lowden

Exposure to the Helicobacter pylori microbe is potentially linked to more than one in five cases of colorectal cancer, according to an analysis, but researchers say long-term studies are needed to prove if eradication therapy would lower the risk.

The bacterium is categorised as a human carcinogen because of its established causal association with stomach cancer. However, the link between H. pylori and colorectal cancer remains “highly controversial”, which is what prompted this latest study.

The international research team, led the University of Hong Kong and the University of California San Diego, analysed data from reviews of 43 previous studies involving nearly 49 million people and combined it with estimates from the Global Cancer Observatory.

The analysis, published in eGastroenterology, found that exposure to H. pylori is linked to a 1.59-fold increased risk of colorectal cancer, compared to not being exposed.

It also found that exposure may be linked to a fifth (22%) of cases. The estimated proportion attributable to exposure was much lower, however, when restricted to 14 population-based and cohort studies (12%).