Abstract
BACKGROUND: While a close association between gastric mucosa associated lymphoid tissue (MALT) lymphoma and Helicobacter pylori infection has been established, there are still cases which do not respond to H pylori eradication. AIMS: To investigate the clinicopathological factors which may help predict the therapeutic efficacy of H pylori eradication in gastric MALT lymphoma. PATIENTS: Forty one patients with gastric MALT lymphoma, including low and high grade lesions. METHODS: After endosonographic staging was determined, H pylori was eradicated in all patients, and the subsequent gastric pathological course was then investigated. RESULTS: Complete regression of MALT lymphoma was observed in 29(71%) patients, partial regression in five (12%), and no regression in seven (17%). Twenty six (93%) of 28 MALT lymphomas restricted to the mucosa but only three (23%) of 13 lymphomas which invaded the deep portion of the submucosa or beyond completely regressed. Kaplan-Meier analysis for the probability of complete regression of MALT lymphoma revealed a significant difference between tumours restricted to the mucosa and those invading the submucosa deeply or beyond (p<0.05). Neither the presence of a high grade component, perigastric lymphadenopathy, nor clinical staging prior to eradication correlated with the probability of lymphoma regression. CONCLUSIONS: Assessment of deep submucosal invasion by endosonography is valuable for predicting the efficacy of H pylori eradication in gastric MALT lymphoma.