Patients with early gastric cancer who receive H. pylori eradication treatment after endoscopic resection have lower rates of metachronous gastric cancer.
The findings, from a single centre in South Korea, obviously have particular implications for East Asian and other high incidence countries.
However Monash University’s Professor of Cancer Research John Zalcberg told the limbic the study was certainly of interest even in countries such as Australia where H. pylori was less prevalent.
“It helps confirms H. pylori as a carcinogen and the reduction in metachronous gastric cancer in this population makes a difference.”
The randomised controlled trial of 470 patients found 7.2% of treated patients developed metachronous gastric cancer during a median follow-up period of six years compared to 13.4% of patients who received placebo.
Treatment for H. pylori was also associated with a significant improvement in glandular atrophy at the corpus lesser curvature (48.4 v 15.0 %; OR 5.30) and an improved grade of intestinal metaplasia at the same site (36.6 v 18.3%).
However triple therapy for H. pylori failed to make a difference to secondary outcomes including incidence of metachronous adenomas (16 v 17 patients) and death from any cause (11 v 6 patients).
Although the study did not confirm Helicobacter eradication or provide salvage treatment where eradication might have failed, it strengthens evidence for the association between the bacteria and gastric cancer.
“We speculate that persistent inflammation of the gastric mucosa with H. pylori infection promotes carcinogenesis and also increases tumour growth or invasiveness. H. pylori eradication reduces, but cannot completely abolish, the risk of metachronous gastric cancer,” they said.
Professor Zalcberg questioned the relevance of the findings in patients with more advanced gastric cancer.
He said eradicating the infection was somewhat analogous to getting people to quit smoking.
“No one questions that smoking is a risk factor for lung cancer. If we stop smoking, there is less damage to cells and people are less likely to get lung cancer.”
“However once a cancer has started, it won’t go away by not smoking. You might get a better outcome but you won’t make it disappear.”
He added that high salt diets in Asia and perhaps fermented foods also contributed to inflammation, rapid turnover of cells and cellular damage in the stomach.
However in Australia and other Western countries, obesity was likely the more important risk factor for the increasing incidence of tumours especially of the oesphagogastric junction.