Antibiotic therapy in nongastrointestinal MALT lymphoma: a review of the literature

Although antibiotic therapy has been established as the standard of care in patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma, much less is known about the value of antibiotic therapy in nongastrointestinal (non-GI) MALT lymphomas. A computerized search (Medline) accompanied by a manual search to identify clinical reports on the topic of antibacterial therapy in patients with non-GI MALT lymphomas was performed. The majority of data were available for MALT lymphoma of the ocular adnexa (OAML) including a total of 131 patients in 4 retrospective studies, 3 prospective series (including 81 patients), and 1 case report. Treatment was exclusively targeting Chlamydophila psittaci (CP), using doxycycline in all but 2 studies. The median follow-up for these studies was 25 months, and both CP-positive as well as CP-negative patients responded. Complete remission was achieved in 23 patients (18%), 36 (27%) had a partial remission, 55 (42%) had stable disease, and 8 patients (6%) had progressive disease accounting for an overall response rate of 45%. In the largest study, a better response was suggested in CP-positive patients. By contrast, only scattered reports could be found for other non-GI localizations, allowing no conclusion about the benefit of antibiotic therapy and probably resulting in a publication bias toward positive cases. Based on these results, antibiotic therapy using doxycycline appears to be a reasonable first-line therapy for patients with OAML. Antibiotics, however, remain experimental for the time being in patients with other non-GI MALT lymphomas. Further preclinical studies as well as large-scale therapeutic trials are warranted to define the role of antibiotic therapy in such patients.