Peptic ulcers and gastric cancer.

It is now believed that a large proportion of peptic ulcers, and possibly some gastric cancers, are initiated by infection with Helicobacter pylori. The natural habitat of this bacterial organism is the stomach, and in some populations its presence is ubiquitous. The mode of transmission of the organism is unclear but is believed to be primarily by the faecal-oral route. With improved living standards in developed countries infection rates, particularly in children, appear to be decreasing. Formerly, a commonly accepted explanation for the production of peptic ulcers was excess acid production. The rationale of treatment was to limit acid production or to protect the surface from damage. These treatments can be very effective, but once the treatment course is stopped the damage is likely to recur. The recognition that most cases of peptic ulcer are probably initiated by H. pylori has resulted in new treatments designed to eradicate the organism. This can be very effective and lead to permanent cure, but currently there are problems concerning response rates and increasing resistance by the organism. Gastric cancers are the result of a sequence of changes, some of which may be initiated by H. pylori. Even if it were possible, the eradication of H. pylori will not completely remove the public health problem of either peptic ulcers or gastric cancer. The rarer adenocarcinoma of the cardia is produced independently of infection by the organism and is increasing in incidence.