Outcomes In Splenic Marginal Zone Lymphoma: Analysis Of 108 Patients Treated In British Columbia (BC)
Authors: He Xing Katharine , Kahlon Amrit , Connors Joseph M. , Skinnider Brian , Gascoyne Randy D. , Sehn Laurie H. , Savage Kerry J. , Slack Graham W. , Shenkier Tamara , Klasa Richard , Gerrie Alina S. , Villa Diego 
Published: October 2019

Abstract

Introduction
Splenic marginal zone lymphoma (SMZL) is uncommon and accounts for less than 1% of all non-Hodgkin lymphomas. The optimal treatment for SMZL is unknown. We describe the outcome of 108 patients with SMZL treated in British Columbia.

Methods
All patients with SMZL diagnosed between 1985 and June 2012 were identified in the BC Cancer Agency Centre for Lymphoid Cancer and Lymphoma Pathology Databases. Overall survival (OS) was measured from time of diagnosis to death or last follow-up. Progression-free survival (PFS) was measured from the date of diagnosis to the date of lymphoma recurrence or transformation, or death. Time to transformation (TTT) was calculated from date of diagnosis to date of transformation to aggressive lymphoma.

Results
108 patients were identified with a diagnosis of SMZL. Baseline patient characteristics: median age 67 years (range 30-88), male 41%, stage IV 98%, B symptoms 17%, performance status ≥2 22%, splenomegaly 93%, bone marrow involvement 93%, peripheral blood involvement 87%. Hepatitis C serology was positive in 5 of 60 patients with available data.
As initial treatment, 53 underwent splenectomy (10 with chemotherapy), 38 chemotherapy alone (21 with a rituximab-containing regimen), 2 received antiviral therapy for hepatitis C, and 15 were observed. Of the 43 patients who had splenectomy alone, 9 subsequently received chemotherapy upon progression, 1 had excision for a soft tissue mass, and 4 transformed to diffuse large B cell lymphoma (DLBCL). Of the 38 who received chemotherapy first line, 6 subsequently received combined chemotherapy and splenectomy, 1 splenectomy alone, 4 chemotherapy alone, and 7 transformed to DLBCL. Neither of the 2 patients who received antivirals had further progression.
With a median follow-up of 7 years (range 3 months to 18 years) for living patients, the 5 and 10 year OS were 65% and 48%, respectively. The 5 and 10 year PFS were 38% and 18%, respectively. The 5 year OS for patients who had a splenectomy as their first-line therapy compared to other treatments was 76% vs 53% (p=0.01); and the 5 year OS for patients who received chemotherapy alone as first-line compared to other treatments was 52% vs 72% (p=0.04). There was no difference in outcomes between those treated with rituximab containing chemotherapy as first line compared to other treatments (p=0.65). The 5 and 10 year PFS after first-line splenectomy were 52% and 18%, respectively. A total of 14 patients transformed to DLBCL with a median TTT of 3.2 years (range 6 months to 11.9 years). The 5, 10, 15 year rates of transformation were 9%, 21% and 35%, respectively.

Conclusions
Splenectomy remains a reasonable treatment option for patients with SMZL. Patients selected for splenectomy as initial management of symptomatic disease experience improved outcomes. The transformation rate in SMZL is similar to that of other indolent lymphomas.

Disclosures:
Connors: F Hoffmann-La Roche: Research Funding; Roche Canada: Research Funding. Skinnider:Roche Canada: Research Funding. Gascoyne:Roche Canada: Research Funding. Sehn:Roche Canada: Research Funding. Savage:Roche Canada: Research Funding. Slack:Roche Canada: Research Funding. Shenkier:Roche Canada: Research Funding. Klasa:Roche Canada: Research Funding. Gerrie:Roche Canada: Research Funding. Villa:Roche Canada: Research Funding.