Treatment of Splenic Marginal Zone Lymphoma With Rituximab Monotherapy: Progress Report and Comparison With Splenectomy

Abstract

Background. Treatment of splenic marginal zone lymphoma (SMZL) patients is not standardized. Recent data suggest that rituximab is highly effective and could be considered as initial therapy. Aim. To assess the efficacy of rituximab monotherapy in a large series of patients with SMZL and compare these results with splenectomy results. Methods. The studied population included 85 patients. Fifty-eight received rituximab at a dose of 375 mg/m² per week for 6 weeks as induction followed by maintenance at the same dose every 2 months for 1–2 years, whereas 27 patients were treated using splenectomy only. Results. The overall response rate to rituximab 2 months after the end of induction was 95% (complete response [CR], 45%; unconfirmed CR, 26%; partial response, 24%). The median times to hematologic and clinical response were 2 weeks and 3 weeks, respectively. Forty-three of 55 patients already completed the maintenance phase: 28 sustained their initial response, 14 improved their response, and one progressed. Eighty-five percent of splenectomized patients responded, and two were treated with rituximab as consolidation after splenectomy and achieved a CR. The 5-year overall and progression-free survival (PFS) rates for rituximab-treated and splenectomized patients were 92% and 77% (p = .09) and 73% and 58% (p = .06), respectively. Furthermore, maintenance therapy with rituximab resulted in a longer duration of response (at 5 years, PFS was 84% for patients receiving maintenance and 36% for patients without maintenance, p <.0001). Conclusions. Rituximab is a very effective and well-tolerated therapy and may be substituted for splenectomy as the first-line treatment of choice for patients with SMZL.