Long-term outcomes of gastric mucosa-associated lymphoid tissue lymphomas after Helicobacter pylori eradication therapy

Mucosa-associated lymphoid tissue (MALT) lymphomas are localized primarily in the gastrointestinal tract and are characterized by an indolent nature and favorable outcome with specific therapy. Gastric MALT lymphomas are closely linked to Helicobacter pylori (H. pylori) infection, for which eradication therapy is recognized as an effective primary treatment for the disease. However, there is little information about long-term outcomes after the therapy. In the present study, we elucidated the long-term outcomes of 74 patients (70 H. pylori-positive and 4 negative cases) followed up by endoscopy at least 12 months after exclusive eradication therapy alone. The median follow-up period was 46 months. When the remission status was estimated at the time point of 12 montihs post-eradication, the numbers of patients with complete remission (CR), histologically residual disease with macroscopic normalization (hRD), partial remission with more than 50% tumor reduction (PR) or no response (NR) were 56, 12, 2 and 4, respectively. During follow-ups of over 12 months post-eradication, 11 of the 12 hRD cases were belatedly induced to CR but one CR case histologically relapsed into hRD. One of the 2 PR cases eventually turned into hRD 20 months later. Therefore, 66 CR, 3 hRD, 1 PR, and 4 NR cases (including 3 H. pylori-negative) were identified at the last follow-up of the present study. All 74 patients were followed up without any second-line therapies, but none exhibited disease progression. Thus, the long-term outcome of localized gastric MALT lymphoma after H. pylori eradication therapy was favorable. A watch and wait strategy may be a reasonable approach for hRD since the majority might be in the process of turning into delayed CR.