Helicobacter pylori eradication for the treatment of low-grade gastric MALT lymphoma: Follow-up together with sequential molecular studies

Background: Helicobacter pylori infection is associated with low-grade gastric MALT lymphoma, and available data support that the eradication of the H. pylori can cause histological regression of the lymphoma. Patients ann methods: Nine patients with low-grade gastric MALT lymphoma were treated with amoxicillin, metronidazole, and omeprazole for 14 days in a prospective study. Patients were followed up with sequential endoscopy, mapping gastric biopsies, and molecular studies with PCR amplification of the IgH gene in order to assess the response to H. pylori eradication and the evolution of the histological and molecular responses. Results: H. pylori was eradicated in all patients and reinfections were not demonstrated. After H. pylori eradication treatment, the lymphoma regressed both endoscopically and histologically in eight of the nine patients (88.8%). In four of the eight histologically cured patients, no clonal band was detected by PCR; in the remaining four patients; PCR identified a clonal band, which disappeared in all patients after a mean of 12 +/- 4 months. No clonal band was detected by the PCR analysis in any of the eight patients with histological regression after a median of 7 +/- 6 months (range 1-20). The seven followed-up patients have a persistent clinical and histological remission after a median of 14 +/- 5 months. Conclusions: (I) Low-grade gastric MALT lymphoma can be histologically cured with eradication therapy for H. pylori. (2) After histological regression, PCR amplification of the IgH gene can identify an eventually persisting clonal population. (3) Sequential histological and molecular studies are essential for the assessment of the evolution of the lymphoma. (4) The clonal population tends to disappear, but its disappearance may be delayed for months. (5) Patients with histological regression but with a persistent clonal band should not be treated unless the lymphoma can be histologically demonstrated. All these observations suggest that gastric lymphoma can be effectively cured, but the ultimate fate of these patients is unknown until long-term follow-up studies are available.