Increasing incidence of primary gastric lymphoma.

Both the incidence and mortality rates of gastric cancer have been consistently declining over the past several decades in the United States. In contrast, the incidence of gastric lymphoma may have been increasing during this time. Based on data from the Surveillance, Epidemiology and End Results (SEER) Program, annual incidence rates of gastric lymphoma from 1973 to 1986 were examined. There was a twofold increase in the age-adjusted incidence rates of gastric lymphoma during this time. This increase occurred in both men and women but was limited to people over 60 years of age. Although the reasons for this increase are unknown, the authors speculate that this may be a true increase since neither differences in SEER coding practices nor changes in diagnostic procedures could explain these observations.