Abstract
Helicobacter pylori infection is associated with gastric cancer. A total of 97% of the infected subjects have elevated levels of H. pylori antibodies. The antibody titers have been shown to decline rapidly (40–60% within 4–12 months) only after successful eradication therapy. We allocated 26,700 consecutive patients tested during 1986–1998 for H. pylori antibodies to 3 subcohorts: seropositive patients with rapidly falling antibody titers (Hp+CURED, n = 3,650), seropositive patients where no serological information indicating cure was obtained (Hp+NoInfo, n = 11,638) and seronegative patients (Hp–, n = 11,422). In the subcohorts, the standardised incidence ratios (SIRs) with 95% confidence intervals (CI) were defined for subsequent cancers of stomach, pancreas, colon, rectum, breast and prostate separately and for all cancers except stomach combined. The mean follow‐up time was 10.1 years and the number of gastric cancers was 72. For the Hp+CURED, the SIR for gastric cancers for the first 5 follow‐up years was 1.62 but decreased from the sixth follow‐up year thereon to 0.14 (CI: 0.00–0.75). Likewise, the risk ratio, defined in a Poisson regression analysis using the Hp+NoInfo group as the reference, decreased from 1.60 to 0.13 (CI: 0.02–1.00, p = 0.049). The SIR for Hp– was not significantly higher than that for Hp+NoInfo for any of the cancers analysed. To conclude, cured H. pylori infection led to a significantly decreased incidence of gastric cancers from the sixth follow‐up year. Advanced atrophic gastritis would be a plausible contributor to the elevated SIR in elderly Hp– patients.