Gastric Lymphoma

Primary gastric lymphoma accounts for less than 5 percent of all gastric cancers.1,2 The incidence and pathophysiology of gastric lymphomas differ clinically from the more common adenocarcinomas of the stomach. Unlike adenocarcinoma, primary gastric lymphoma generally responds to current treatment modalities, which include surgery, chemotherapy, and radiotherapy. Gastric lymphoma presents in the sixth decade of life, rarely occurring under the age of 40 years.1,3 Men and women are equally affected. Whereas gastric cancer has been on the decline in the United States, gastric lymphoma has steadily increased.4 According to data from the Surveillance, Epidemiology and End Results (SEER) program and some isolated reports, there has been a nearly twofold increase in the incidence of primary gastric lymphoma within the last two decades.4,5 The age-adjusted incidence has especially risen in the population over 60 years of age.4 This rise in incidence has gained considerable attention due to the increasing awareness of Helicobacter pylori and mucosa-associated lymphoid tissue lymphomas. Patients with primary gastric lymphoma demonstrate an increased risk for other malignancies.6 This association with other cancers coincidentally occurs with lymphomas (both Hodgkin’s and nonHodgkin’s) that affect the peripheral lymph node tissue. The incidence of associated cancers in reported series of patients with primary gastric lymphoma can be as high as 20 to 25 percent.7,8 Whereas many of these patients present with other lymphoid neoplasms, synchronous or metachronous gastric adenocarcinoma develops with relative frequency. One particular series from Japan estimated the incidence of synchronous gastric adenocarcinoma and lymphoma at 3.7 percent.9 Although it is speculative that Helicobacter pylori may play a common role in these patients through malignant degeneration along epithelial and/or lymphoid lines, H. pylori has been documented in patients with synchronous and metachronous primary gastric lymphoma and adenocarcinoma.9