Treating H. pylori reduces metachronous gastric cancer risk
medwireNews: Antibiotic therapy for Helicobacter pylori in patients with early gastric cancer is associated with a 50% lower risk for subsequent disease, trial findings indicate.
The investigators explain that “[e]ndoscopic resection is indicated for early gastric cancers that are not at risk for lymph-node metastasis,” but as the procedure preserves the stomach, “metachronous gastric cancers can develop, with an incidence of approximately 3% per year.”
And the role of H. pylori eradication for the prevention of metachronous disease is unclear, with previous studies demonstrating “conflicting results,” they add.
The current trial – a phase III study conducted at the National Cancer Center in Goyang, South Korea – recruited 396 H. pylori-positive patients who had undergone endoscopic resection for early gastric cancer or high-grade adenoma. Participants were randomly assigned to receive either H. pylori eradication therapy, comprising 7 days of twice-daily treatment with the the antibiotics amoxicillin 1000 mg and clarithromycin 500 mg plus the proton pump inhibitor rabeprazole 10 mg for 5 weeks, or placebo pills and rabeprazole.
Over a median follow-up of 5.9 years, 7.2% of patients in the H. pylori treatment arm developed metachronous gastric cancer (defined as disease occurring no earlier than a year after resection), as did 13.4% of those in the placebo arm, giving a significant hazard ratio of 0.50 in favor of treatment.
Assessment of glandular atrophy in the gastric corpus lesser curvature – a co-primary endpoint – showed an improved grade at the 3-year mark in a significantly higher proportion of participants who received treatment versus placebo, with corresponding rates of 48.4% and 15.0%, and an odds ratio of 5.30.
The grade of intestinal neoplasia in the corpus lesser curvature also improved in significantly more antibiotic-treated patients than controls, at 36.6% and 18.3%, respectively, report Il Ju Choi and co-researchers, from the National Cancer Center, in The New England Journal of Medicine.
However, there was no significant improvement with treatment in the grade of glandular atrophy or intestinal neoplasia in the antrum, and the incidence of metachronous adenomas and overall survival were also comparable between study groups.
H. pylori eradication therapy was associated with a significantly higher incidence of treatment-related adverse events than placebo (42.0 vs 10.2%), but the toxicities – most commonly taste alteration, diarrhea, and dizziness – were mild and there were no serious adverse events.
Noting that the endoscopic procedure leaves the atrophic gastric mucosa in a precancerous “alarm state,” editorialist Peter Malfertheiner (Otto von Guericke University Magdeburg, Germany) says that it is “striking” that H. pylori treatment “may be still be effective at this stage.”
He points out, however, that the intervention was effective only in a subgroup of patients, “so endoscopic or histologic surveillance remains mandatory.”
“This requirement extends to all patients with severe atrophic gastritis with or without intestinal metaplasia even after successful eradication,” Malfertheiner writes. “Since the selection of eradication therapy is aimed at minimizing the development of antimicrobial resistance, bismuth-based regimens should be given preference.”
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