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 univer sity 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) tetracy cline, 500 mg four times daily, and clarithromycin, 500 mg three times dail y; or 3) tetracycline, 500 mg four times daily, and metronidazole, 500 mg t hree times daily-were administered sequentially (usually in the order writt en) for 21 days at baseline and at 8 weeks, along with a proton-pump inhibi tor (lansoprazole or omeprazole) and bismuth subsalicylate. Measurements: Complete remission was defined as the absence of histopatholo gic evidence of lymphoma on endoscopic biopsy. Partial remission was define d 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-positiv e patients, 14 (50% [95% CI, 31% to 69%]) achieved complete remission, 8 (2 9%) achieved partial remission (treatment eventually failed in 4 of the 8), and 10 (36% [CI, 19% to 56%]) did not respond to treatment. Treatment fail ed in all 6 (100% [CI, 54% to 100%]) H. pylori-negative patients. Patients with endoscopic appearance of gastritis (stage I T1 disease) were most like ly to achieve complete remission within 18 months. Tumors in the distal sto mach were associated with more favorable response than tumors in the proxim al stomach. Conclusions: A subset of H. pylori-positive gastric MALT lymphomas, includi ng infiltrative tumors, may respond to antibiotics. The likelihood of: earl y complete remission seems to be greatest for superficial and distal tumors .