Splenic marginal zone lymphoma: excellent outcomes in 64 patients treated in the rituximab era

Splenic marginal zone lymphoma (SMZL) is a rare non-Hodgkin lymphoma. We sought to identify prognostic factors and define outcomes in a cohort of 64 patients with SMZL who were treated at two large academic medical centers in North America in the rituximab era.

Over a median follow-up of 37.8 (range 6-167.1) months, Kaplan-Meier estimate of median OS was 156.3 months and median PFS was 52.9 months. On univariate analysis, baseline hemoglobin <12 g/dl was associated with inferior OS (p = 0.045). High-risk FLIPI score was associated with inferior PFS when compared with intermediate/low risk (p = 0.05) and marginally significant with regard to OS (p = 0.056). Splenectomy was not predictive of OS or PFS (p = 0.563 and 0.937, respectively). Transformation to diffuse large B-cell lymphoma occurred in four (6.3%) patients during the observation period. OS was comparable to contemporaneous cohorts of patients with extranodal and nodal marginal lymphomas and FLIPI score was highly predictive for inferior PFS and OS when all three cohorts were analyzed together.

Outcomes of SMZL, in our series, were excellent, with a median OS of >13 years. Low hemoglobin and high-risk FLIPI were associated with inferior outcomes.