By removing Helicobacter pylori bacteria from gastric cancer patients after surgery can reduce the odds of cancer redevelopment dramatically, according to an article released on August 1, 2008 in The Lancet.

H. plyori is a virus that usually infects the stomach or small intestines. Once the initial has been removed, another cancer may appear in a different part of the stomach, in what is called a metachronous cancer. Infection of the mucosal lining of the stomach has been associated with almost all stomach cancers, and the WHO has classified the bacteria as a group I carcinogen for this stypie of cancer. In animal models, H. plyori removal prevents stomach cancer, but results of human trials have been mixed.

To help elucidate the effects of H. pylori removal on the prophylaxis of metachronous stomach cancer, Dr Mototsugu Kato and Dr Masahiro Asaka, Hokkaido University Graduate School of Medicine, Japan Gast Study Group performed a randomized controlled trial of 544 patients. Each patient was either newly diagnosed with stomach cancer and planning to have endoscopic treatment or was in pos-resection follow-up after this treatment. Subjects were randomly assigned to one of two groups: a test population administered 30 mg lansoprazole twice per day, 750 mg amoxicillin twice per day, and 200 mg clarithromycin twice daily for a week; and a control population administered or standard care but no additional treatment to eradicate H. pylori.

During a three year follow-up, metachronous gastric cancer developed in 9 patients in the eradication group (3.3%) and 24 in the control group (8.8%). Overall, the risk of this type of cancer was reduced to one third of the control risk using this treatment. However, it is notable that in the group receiving eradication treatment, 19 patents had diarrhea (7%) and 32 had soft stools (12%).

The authors conclude optimistically: “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.”

Dr Nicholas Talley, Mayo Clinic Jacksonville, Florida, USA contributed an accompanying comment which emphasizes the importance of the investigation of stomach cancer: “Colonoscopy is used to screen for colorectal cancer in many countries, although direct evidence from published randomised trials of benefits versus risks are not available. Yet, worldwide, gastric cancer kills more people, and there is better evidence that H pylori eradication can prevent mortality than there is for colonoscopy screening. Preventing gastric cancer by eradicating H pylori in high-risk regions should be a priority.”

Effect of eradication of Helicobacter pylori on incidence of metachronous gastric carcinoma after endoscopic resection of early gastric cancer: an open-label, randomised controlled trial
Kazutoshi Fukase, Mototsugu Kato, Shogo Kikuchi, Kazuhiko Inoue, Naomi Uemura, Shiro Okamoto, Shuichi Terao, Kenji Amagai, Shunji Hayashi, Masahiro Asaka, for the Japan Gast Study Group*
Lancet 2008; 372: 392-97
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Written by Anna Sophia McKenney