OBJECTIVES: I. Determine the rate of eradication of Helicobacter pylori using omeprazole, colloidal bismuth subcitrate, tetracycline, and metronidazole in patients with low grade gastric lymphoma. II. Determine the macroscopic/endoscopic and microscopic healing/remission rate after eradication of Helicobacter pylori in this patient population. III. Determine the natural history of low grade gastric lymphoma after eradication of Helicobacter pylori.

OUTLINE: This is a nonrandomized, open label, multicenter study. Patients receive oral omeprazole bid on days 1-10, oral bismuth subcitrate and oral tetracycline qid on days 4-10, and oral metronidazole tid on days 4-10.

Patients are evaluated at 8 weeks. Patients who experience complete remission and are H. pylori negative proceed to follow up. Patients with complete remission or no change but who are H. pylori positive proceed to a second course of therapy with the previous schedule or with omeprazole bid, amoxicillin qid, and clarithromycin tid for 14 days. Patients who experience no change but are H. pylori negative are followed at 6 and 9 months and restaged. Patients are followed at 6, 9, 12, 18, and 24 months, then annually thereafter.

PROJECTED ACCRUAL: Approximately 60-96 patients will be accrued for this study.