Histologische und molekulare Befunde bei 120 Patienten mit MALT-Lymphom des Magens nach Eradikation von Helicobacter pylori

A longtime infection of the gastric mucosa with Helicobacter pylori is a known causal factor in the pathogenesis of gastric MALT-Lymphoma. Since 1993 eradication therapy has been an accepted treatment of stage EI1 diseases. The following dissertation presents the results of a prospective multicenter study enclosing 120 patients with MALT-Lymphoma stage EI1 and Helicobacter pylori infection. An observation time of median 85 month with regular endoscopic controlling was followed by analyses of the histological, molecular and clinical outcome. The patients had been examined prospectively with regard to B-cell-clonality and retrospectively concerning translocation t(11;18)(q21,21). Complete remission of the gastric MALT-Lymphoma after an HP-eradication as initial therapy was achieved in 80% of the patients. Again 80% of these Patients showed a continuous complete remission during the whole follow up. In addition to three macrocopic relapses, we found a so called “histological residual disease (hRD)” in 16 cases. For these patients a “watch and wait”-strategy with continuous endoscopic inspections was chosen. As all of these patients achieved a second complete remission without additional therapy we recommend this “watch and wait”-strategy. A detailed analysis of the association between histological and molecular findings revealed the following: • The histological criteria of lymphoma regression “empty tunica propria” and “fibrosis of tunica propria” are prognostically relevant. If these criteria are existent in several consecutive biopsies there will be presumably a complete remission of the lymphoma. We recommend the observation of patients with partial remission and histological signs of tumor regression for a period of two years. • The appearance of reactive aggregates of lymphocytes without evidence of lymphoma is not associated with an increased risk of relapse. It should not be named a “probable minimal residual disease” as done in the GELA-classification. • In several studies monoclonal B-Cell lymphocytes were detected even after complete histological remission. We analysed the association between persistent monoclonality and the course of disease. The study revealed a statistically elevated risk for relapse or hRD for patients with persistent evidence of monoclonal B-cells. But regardless the majority of these patients stays in CCR. If there is a complete histological remission of lymphoma, the clinical relevance of monoclonal bands in PCR is arguable. For that reason a routinely molecular follow up is not recommended. • The translocation t(11;18)(q21;21) is associated with an adverse course of disease. As patients with t(11;18) can also stay in continuous complete remission, a “watch and wait”-strategy seems to be justifiable in these patients, too. • The precancerous lesions “intestinal metaplasia” and “atrophy of gastric mucosa” may develop on the basis of permanent inflammatory stimuli. They present in 30% of the examinations. Once a pathologic gastric mucosa is developed, it will not reform itself after HP-eradication. In summary the beneficial course of MALT-lymphoma of the stomach stage EI1 hould be pointed out.