Predictive factors for regression of gastric MALT lymphoma after anti-Helicobacter pylori treatment.

BACKGROUND AND AIMS Discrepant remission rates (41-100%) have been reported for patients with localised low grade gastric mucosa associated lymphoid tissue (MALT) lymphoma after eradication of Helicobacter pylori. The aim of this study was to explain these discrepancies and to determine the predictive factors of gastric lymphoma regression after anti- H pylori treatment. PATIENTS AND METHODS Forty six consecutive patients with localised gastric MALT lymphoma (Ann Arbor stages I(E) and II(E)) were prospectively enrolled. All had gastric endoscopic ultrasonography and H pylori status assessment (histology, culture, polymerase chain reaction, and serology). After anti-H pylori treatment, patients were re-examined every four months. RESULTS Histological regression of the lymphoma was complete in 19/44 patients (43%) (two lost to follow up). Median follow up time for these 19 responders was 35 months (range 10-47). No regression was noted in the 10 H pylori negative patients. Among the 34 H pylori positive patients, the H pylori eradication rate was 100%; complete regression rate of the lymphoma increased from 56% (19/34) to 79% (19/24) when there was no nodal involvement at endoscopic ultrasonography. There was a significant difference between the response of the lymphoma restricted to the mucosa and other more deep seated lesions (p<0.006). However, using multivariate analysis, the only predictive factor of regression was the absence of nodal involvement (p<0.0001). CONCLUSION In H pylori positive patients with localised gastric MALT lymphoma, carefully evaluated and treated without any lymph node involvement assessed by endoscopic ultrasonography, complete remission of lymphoma was reached in 79% of cases.