Risk of pancreatic cancer after eradication treatment of Helicobacter pylori.

[OBJECTIVES] Helicobacter pylori infection seems to increase the risk of developing pancreatic cancer, but it is unknown whether eradication treatment of this bacterium changes this risk. We hypothesized that the increased risk of pancreatic cancer among individuals infected with Helicobacter pylori decreases over time after eradication treatment.

[METHODS] This multinational and population-based cohort study, using prospectively collected nationwide register data from 1995 to 2019, included all adults who received eradication treatment for Helicobacter pylori in Denmark, Finland, Iceland, Norway, or Sweden. Standardized incidence ratios (SIR) with 95 % confidence intervals (95 %CI) were calculated by dividing the incidence rates of pancreatic cancer in the eradication treatment cohort by that of the entire populations of the corresponding age, sex, calendar year, and country. The main outcome was changes in SIR over time after eradication treatment.

[RESULTS] During up to 24 years of follow-up of 661,827 participants and 5494,255 person-years in the eradication treatment cohort, 2331 participants developed pancreatic cancer. The risk of pancreatic cancer was increased during the first 1-5 years after eradication treatment (SIR 1.14, 95 % CI 1.07-1.21), after which it decreased and became similar to the level of the background population 6-10 years (SIR 0.99, 95 % CI 0.92-1.07) and 11-24 years (SIR 1.00, 95 % CI 0.92-1.08) after eradication treatment.

[CONCLUSION] The elevated risk of developing pancreatic cancer among individuals with Helicobacter pylori infection seems to decrease after eradication treatment, reaching the risk estimates of the background population.