Post-op removal of key bacteria reduces stomach cancer recurrence

Removing 'Helicobacter Pylori' bacteria from the stomachs of post-operative gastric cancer patients can massively reduce the odds of such cancer redeveloping, concludes a report published in this week’s edition of The Lancet.

Almost all stomach cancers not related to the heart develop from H Pylori infected mucosa (the lining of the stomach), and as such WHO has classified the bacteria as a group I carcinogen for stomach cancer. And while removal of H Pylori has a prophylactic effect on stomach cancer in animal models, results of trials in human beings have been controversial, with some studies showing a prophylactic effect while others show that the removing the bacteria does not significantly decrease the incidence of gastric cancer.

Dr Mototsugu Kato and Dr Masahiro Asaka, Hokkaido University Graduate School of Medicine, Japan, and colleagues from the Japan Gast Study Group carried out a randomised controlled trial of 544 patients to investigate the possible prophylactic effect of H pylori eradication on the development of metachronous stomach cancer after surgery to remove early gastric cancer. Metachronous cancer is cancer that develops after the surgery to remove the initial cancer, but does not develop from that initial cancer, ie, it develops at a new site in the stomach.

All patients were newly diagnosed and planning to have endoscopic treatment or in post-resection follow up after endoscopic treatment. Patients with early stomach cancer were randomised to receive either an H pylori eradication regimen (272 patients) or no treatment (272). The eradication group received lansoprazole 30 mg twice daily, amoxicillin 750 mg twice daily, and clarithromycin 200 mg twice daily for a week; the control group received standard care but no additional treatment to remove H pylori. Patients were then examined endoscopically at 6, 12, 24 and 36 months to see if a new cancer had developed at a different site in the stomach.

The researchers found that, at 3-year follow-up, metachronous gastric cancer had developed in 9 patients in the eradication group and 24 in the control group. Overall, the risk of developing such cancer was reduced by around two thirds in the eradication group compared with the control group. In the eradication group, 19 (7%) of patients had diarrhoea and 32 (12%) had soft stools.

They conclude: “The results of our study suggest that treatment to eradicate H pylori reduces the risk of developing new gastric carcinoma in patients who have a history of such disease and are thus at risk for developing further gastric cancers...we believe that our data add to those from previous studies showing a causal relationship between H pylori infection and gastric cancer, and also support the use of H pylori eradication to prevent the development of gastric cancer.”