Antibiotic treatment of gastric lymphoma of mucosa-associated lymphoid tissue - An uncontrolled trial

Background: Gastric lymphoma of mucosa-associated lymphoid tissue (MALT) is related to Helicobacter pylori infection and may depend on this infection for growth. Objective: To determine the response of gastric MALT lymphoma to antibiotic treatment. Design: Prospective, uncontrolled treatment trial. Setting: University hospital referral center and three collaborating university and community hospitals. Patients: 34 patients with stage I or stage II N1 gastric MALT lymphoma. Intervention: Two of three oral antibiotic regimens-1) amoxicillin, 750 mg three times daily, and clarithromycin, 500 mg three times daily; 2) tetracycline, 500 mg four times daily, and clarithromycin, 500 mg three times daily; or 3) tetracycline, 500 mg four times daily, and metronidazole, 500 mg three times daily-were administered sequentially (usually in the order written) for 21 days at baseline and at 8 weeks, along with a proton-pump inhibitor (lansoprazole or omeprazole) and bismuth subsalicylate. Measurements: Complete remission was defined as the absence of histopathologic evidence of lymphoma on endoscopic biopsy. Partial remission was defined as a reduction in endoscopic tumor stage or 50% reduction in the size of large tumors. Results: 34 patients were followed for a mean (+/-SD) of 41 +/- 16 months (range, 18 to 70 months) after antibiotic treatment. Of 28 H. pylori-positive patients, 14 (50% [95% CI, 31% to 69%]) achieved complete remission, 8 (29%) achieved partial remission (treatment eventually failed in 4 of the 8), and 10 (36% [CI, 19% to 56%]) did not respond to treatment. Treatment failed in all 6 (100% [CI, 54% to 100%]) H. pylori-negative patients. Patients with endoscopic appearance of gastritis (stage I T1 disease) were most likely to achieve complete remission within 18 months. Tumors in the distal stomach were associated with more favorable response than tumors in the proximal stomach. Conclusions: A subset of H. pylori-positive gastric MALT lymphomas, including infiltrative tumors, may respond to antibiotics. The likelihood of: early complete remission seems to be greatest for superficial and distal tumors.