Rituximab monotherapy is highly effective in splenic marginal zone lymphoma

Splenectomy has traditionally been considered as a standard first line treatment for splenic marginal zone lymphoma (SMZL) conferring a survival advantage over chemotherapy. However it carries significant complications, especially in elderly patients. The purpose of this retrospective study was to report our experience on the efficacy of Rituximab as first line treatment in 16 consecutive SMZL patients, diagnosed in our department. The diagnosis was established using standard criteria. Patients' median age was 57 years (range, 48-78). Prior to treatment initiation all patients had splenomegaly, nine had anemia, five lymphocytosis, five neutropenia and six thrombocytopenia. Rituximab was administered at a dose of 375 mg/m2/week for 6 consecutive weeks. The overall response rate was 100%. After treatment, all patients had a complete resolution of splenomegaly along with restoration of their blood counts. Eleven patients (69%) achieved a CR, three (19%) unconfirmed CR and two (12%) a PR. Among the complete responders seven patients had also a molecular remission. The median time to clinical response was 3 weeks (range, 2-6). Rituximab maintenance was given to 12 patients. Eleven of them had no evidence of disease progression after a median follow-up time of 28.5 months (range, 14-36), while two out of four patients who did not receive maintenance, relapsed 7 and 24 months after the completion of induction treatment. Median follow-up time for the entire series was 29.5 months (range, 15-81). No deaths were recorded during the follow-up period. Therapy was well tolerated. The present study demonstrates that rituximab is an effective treatment for SMZL and could be considered as a substitute or alternative to splenectomy.