Incidence of gastrointestinal malignancies increases in persons received eradication therapy for Helicobacter pylori: A cohort study

Abstract

Background: Long-term Helicobacter pylori infection increases the risk of gastric malignancies. Since the symptoms for H. pylori gastritis, as well as for several malignancies, may be nonexisting or highly unspecific, even H. pylori-positive subjects with underlying malignancies may receive eradication therapy. The aim was to assess the incidence of gastrointestinal and various other malignancies in individuals after eradication therapy for H. pylori infection.

Materials and methods: A cohort of 217,554 subjects (120,344 women and 97,210 men), who had purchased specific combinations of drugs for H. pylori eradication therapy in 1994-2004, was identified by the Finnish National Prescription Registry and followed for cancer incidence until the end of 2008 (1.89 million person-years at risk).

Results: A total of 22,398 malignancies were identified in the cohort. In both genders, for the first 6 months after drug prescription, the standardized incidence ratios (SIRs) were between 5 and 32 for gastric, colorectal, and pancreatic cancers, and 2 and 3 for several other malignancies. Although later on the SIRs of most malignancies fell rapidly, those of gastric noncardia and lung cancers remained elevated up to 5 years of follow-up. The only SIRs below unity were seen in men for gastric cancers (cardia 0.61, 95% CI: 0.37-0.95; intestinal noncardia 0.74, 95% CI: 0.56-0.97) during the post-therapy period covering years 5-15.

Conclusion: Incidence levels significantly above the population rates were detected for many malignancies. Although eradication of H. pylori may have a long-lasting protective effect against gastric cancer, H. pylori therapy may postpone the detection of malignancies possibly underlying unspecific gastrointestinal symptoms. Therefore, it should be emphasized that the diagnostic work-up for malignancies should not be stopped in case of detection and treatment of H. pylori infection.

Keywords: Helicobacter pylori; cancer epidemiology; eradication therapy; gastric cancer; malignancy.