Eradication of Helicobacter pylori in patients with early-stage gastric cancer reduced the risk of subsequent metachronous gastric carcinoma significantly, compared with controls, in a Japanese study of more than 500 patients.
H. pylori is a known gastric carcinogen, according to the World Health Organization, and its causal effect on the development of gastric cancer has been proved in animal studies, noted the Japan Gast Study Group, which conducted the current study (Lancet 2008;372:392-7).
However, studies of the effect of eradication of the bacterium have had mixed results. Most notably, “a large-scale, double-blind randomized study in China showed that gastric cancer still occurred after successful eradication of H. pylori and that eradication did not lead to a significant decrease in the incidence of gastric cancer” (JAMA 2004;291:187-94).
In the current multicenter, open-label, randomized, controlled study of 544 patients with early gastric cancer who were either planning to have endoscopic treatment or who had just completed resection after endoscopic treatment, half of the patients (272) were given a drug regimen to eradicate the H. pylori bacterium, and half served as controls.
A modified intention-to-treat analysis included 255 patients in the treatment group and 250 patients in the control group, after 17 treatment patients and 22 controls were lost to follow-up. Three-quarters of patients in both groups were men, and all patients were aged 62–73 years.
The treatment group received a combination of lansoprazole 30 mg twice daily, amoxicillin 750 mg twice daily, and clarithromycin 200 mg twice daily for a week. All patients had follow-up clinic visits at 6 months, 1 year, 2 years, and 3 years after randomization, when they were examined endoscopically to see whether new cancer had developed. At these visits, participants also had their H. pylori status confirmed.
“During 3 years of follow-up after endoscopic treatment of primary gastric cancer, metachronous gastric cancer developed in 33 participants—9 in the eradication group and 24 in the control group,” wrote the authors, led by Dr. Kazutoshi Fukase of the department of gastroenterology at Yamagata (Japan) Prefectural Central Hospital. There were no differences between the patients who developed cancer in each group in terms of sex, age, location of the cancer, histologic type, or depth of the invasion of the diameter of the metachronous cancers. “The risk of subsequent cancer was reduced from about 4,000/100,000 individuals a year to 1,400/100,000 individuals a year.”
In an accompanying comment, Dr. Nicholas J. Talley of the department of internal medicine at the Mayo Clinic in Jacksonville, Fla., wrote, “The results are clear: in a high-risk population, gastric cancer rates are substantially reduced, but not abolished, by H. pylori eradication.” The potential risks associated with H. pylori eradication … are small, he added. “Preventing gastric cancer by eradicating H. pylori in high-risk regions should be a priority.”
Both the study authors and Dr. Talley declared that they had no conflicts of interest to disclose.
'Preventing gastric cancer by eradicating H. pylori in high-risk regions should be a priority.' DR. TALLY