Epidemiological and prognostic aspects of gastric MALT-lymphoma.

Since mucosa-associated lymphoid tissue (MALT) lymphoma was defined in the mid-1980s as a clinicopathologic entity, many sets of data on pathological, biological and clinical aspects have been generated. In particular, the finding that this process was responding well to antibiotic treatment fueled interest in it and has led to several clinical trials. This overview deals with epidemiological and prognostic aspects and identifies important questions which need to be answered before data from different sources can be compared. Incidence figures of gastric MALT lymphoma vary between countries and parallel the numbers of all non-Hodgkin's lymphoma. The incidence does not parallel the occurrence data of Helicobacter pylori infection. Incidence figures are highly dependent on the definition used for MALT-type primary gastric lymphomas. Several studies show that some prognostic factors are relevant, for instance stage and grade, whereas other factors such as the International Prognostic Index or treatment are not. These studies do not include the recently introduced antibiotic therapy. The inclusion of recent insights in biology and the treatment of gastric MALT lymphomas in prospective clinical studies will soon answer some of the main questions posed.