Outcomes in splenic marginal zone lymphoma: analysis of 107 patients treated in British Columbia

Splenic marginal zone lymphoma (SMZL) accounts for less than 2% of all non-Hodgkin lymphomas. We identified 107 cases diagnosed with SMZL between 1985 and 2012 from the British Columbia Cancer Agency Centre for Lymphoid Cancer and Lymphoma Pathology Databases. Patient characteristics were: median age 67 years (range 30-88), male 40%, stage IV 98%, splenomegaly 93%, bone marrow involvement 96%, peripheral blood involvement 87%. As initial treatment, 52 underwent splenectomy (10 with chemotherapy), 38 chemotherapy alone (21 chemoimmunotherapy containing rituximab, 1 rituximab alone), two antivirals for hepatitis C, and 15 were only observed. The 10-year overall survival for first-line splenectomy versus chemotherapy was 61% and 42%, respectively [Hazard Ratio (HR) 0·48, 95% confidence interval (CI) 0·26-0·88, P = 0·017]. The 10-year failure-free survival (FFS) after first-line splenectomy vs chemotherapy was 39% and 14%, respectively (HR 0·48, 95% CI 0·28-0·80, P = 0·004). Among the 38 patients who received first-line chemotherapy, FFS was similar between those receiving rituximab (n = 22) and those who did not (n = 16) (HR 0·64, 95% CI 0·31-1·34, P = 0·238). Fifteen patients transformed to aggressive lymphoma with median time to transformation of 3·5 years (range 6 months to 12 years) and the 10-year transformation rate was 18%. In conclusion, splenectomy remains a reasonable treatment for patients with SMZL.