Helicobacter pylori: From the benign to the malignant

Half of the world's population is infected with Helicobacter pylori, making it a pathogen of potentially great significance. Although in the majority of cases, infection is harmless, many infected individuals develop peptic u lcer disease or gastric cancer. In developed countries, the prevalence of i nfection has decreased along with the incidences of duodenal and gastric ul cer and distal gastric cancer. In developing countries, H, pylori infection rates remain high, and, as life expectancy increases, the incidence of gas tric cancer will increase. Recently, a working party of the World Health Or ganization designated H. pylori a class I carcinogen. This designation, alo ng with the description of an H. pylori-infected animal model of gastric ca ncer, has strengthened the case for H. pylori eradication to prevent gastri c cancer. However, concerns are growing that H. pylori eradication itself m ay cause harm. And, in developed countries, an increase in the rate of canc ers arising near the gastroesophageal junction might be linked to the disap pearance of H. pylori. Therefore, we are faced with a dilemma: Should we er adicate H. pylori to prevent cancer of the distal stomach, or should we lea ve it and hence avoid cancer of the proximal stomach or distal esophagus? T he need for more reliable treatments further complicates the issue. So far, we cannot assume that current treatment regimens provide adequate eradicat ion rates to justify widespread screening. Further research is needed to de termine in whom, when, and how to eradicate H. pylori infection. (Am J Gast roenterol 1999; 94 (Suppl.):S11-S16. (C) 1999 by Am. Cell. of Gastroenterol ogy).