Treatment of Helicobacter pylori infection to reduce gastric cancer incidence: Uncertain benefits of a community based programme in Australia

Helicobacter pylori is a cause of gastric adenocarcinoma, but the role of H , pylori eradication in reducing cancer risk is unknown. We sought to estim ate the benefits of a screening and treatment programme for H. pylori infec tion, aimed at reducing the incidence of gastric cancer in Australia. The i mpact of this programme on cancer incidence was evaluated in sensitivity an alyses utilizing Western Australian Cancer Registry data and published data on the epidemiology of H. pylori and gastric cancer. The impact of variati on in parameters used in the sensitivity analyses was substantial, ranging from a 38% reduction in lifetime risk of gastric cancer in a best-case to 3 % in a worst-case scenario. In an intermediate-case scenario there is a 23% reduction in lifetime risk, but in real terms this reflects a fall in cumu lative incidence from 0.7 to 0.5% for males or 0.3 to 0.2% for females. The projected cumulative lifetime incidence of gastric cancer in H. pylori-inf ected males is 2.2% and 0.9% for females; this contrasts with 0.4 and 0.2%, respectively, for those never infected. According to an intermediate-case scenario, to prevent one gastric cancer, screening with or without subseque nt treatment would be required in 617 men or 1639 women. Furthermore, this programme may be less effective in reducing cancer incidence than would be achieved naturally over the next 15 years, providing the current annual dec line in gastric cancer incidence continues. In conclusion, the benefits of a community based programme of H, pylori eradication in terms of cancer ris k reduction remain unclear, related largely to uncertainties in the paramet ers used to calculate these benefits. In Australia, any benefits obtained a re likely to be, at best, modest.