Helicobacter pylori eradication may prevent gastric cancer

Last Updated: 2015-07-27

By Will Boggs MD

NEW YORK (Reuters Health) - Eradication of Helicobacter pylori in healthy asymptomatic individuals may reduce the risk of gastric cancer, according to a systematic review and meta-analysis of six trials, five of which were conducted in Asian populations.

H. pylori infection, which is readily treatable with a short course of antibiotics, appears to increase the risk of developing gastric cancer, but whether eradicating H. pylori in otherwise healthy individuals prevents gastric cancer has remained unclear.

Dr. Paul Moayyedi, from McMaster University, Hamilton, Ontario, Canada, and colleagues undertook a systematic review and meta-analysis to evaluate the effect of H. pylori eradication therapy in preventing gastric cancer in healthy, asymptomatic, H. pylori-positive individuals.

Compared with placebo, H. pylori eradication therapy was associated with a 34% reduction in the risk of gastric cancer, according to the July 22 Cochrane Database of Systematic Reviews online report.

In subgroup analyses, H. pylori eradication therapy did not significantly reduce the risk of gastric cancer in individuals who had preneoplastic lesions or in individuals who did not have preneoplastic lesions at baseline, though the study lacked power to demonstrate such differences.

Similarly, there was no evidence that H. pylori eradication alone reduced the risk of gastric cancer, whereas H. pylori eradication in combination with antioxidants or vitamins was effective. The study lacked power to identify significant differences in these two comparisons, too.

H. pylori eradication had no apparent effect on the risk of esophageal cancer, on the risk of death from gastric cancer, or on all-cause mortality.

"As all but one of the eligible trials we identified were conducted in Asian populations, and the other trial in a South American population, it is not possible to assess the effect of screening and treatment of H. pylori in healthy and asymptomatic individuals in Western populations," the investigators wrote. "In addition, none of the randomized controlled trials we identified reported individual adverse events data, which means that we were unable to assess the balance of benefits and harms if population screening and treatment for H. pylori infection were to be adopted as a public health measure."

"Given that any population-based approach to mass screening for H. pylori, with eradication of the infection in positive individuals, will involve healthy subjects, there needs to be greater confidence in the estimate of effect and more information on any potential harms of H. pylori eradication before such a strategy can be advocated as a means of preventing gastric cancer," they concluded. "Further trials are therefore needed in different populations to extend the evidence base, and these should report on both the benefits and harms of such an approach."

Dr. Francis Megraud, from CHU Pellegrin's bacteriology laboratory, Bordeaux, France, told Reuters Health by email, "We have a lot of indirect data showing that H. pylori infection is the major factor for gastric cancer, but given that gastric cancer occurs several decades after the infection and at relatively low rate, to show in a study that prevention of gastric cancer is possible by H. pylori eradication needs very long studies with a very important number of participants, such as the currently going-on study in Linqu county, China."

Dr. Megraud said that screening and eradication are appropriate for "not all Asians, but in the countries where people are at high risk, such as Japan, Korea, China, and Vietnam. Their risk is higher because of the more virulent strains they harbor, because of their genetic make-up, and also their salty diet, which potentiate the effect."

"Gastric cancer is a preventable cancer!" Dr. Megraud concluded.

Dr. Moayyedi did not respond to a request for comments.

The authors reported no funding or disclosures.

SOURCE: http://bit.ly/1VJE6xT

Cochrane Database Syst Rev 2015.