Transformation and survival in marginal zone lymphoma: a Finnish nationwide population-based study

Abstract

Marginal zone lymphoma (MZL) is an indolent B-cell malignancy with heterogeneous anatomical and clinical presentation. While MZLs are generally associated with long survival, some patients experience histological transformation to aggressive large B-cell lymphoma. Population-based long-term data on the transformation of MZL is limited. We conducted a nationwide population-based study to estimate the risk of transformation and relative survival in patients diagnosed with MZL in Finland from 1995–2018. We identified a total of 1454 patients with MZL from the Finnish Cancer Registry (FCR). The cumulative incidence of transformation was 4.7% (95% CI, 3.6−6.2) at 10 years. The highest incidence of transformation was observed in the patients with splenic MZL (14.0%; 95% CI, 8.6−22.7). The transformation was associated with a substantially increased risk of death (HR, 5.18; 95% CI, 3.58–7.50). Ten-year relative survival was 79% (95% CI, 73‒83%). Transformation, nodal MZL subtype, and older age at diagnosis were associated with increased excess mortality, whereas patients diagnosed at a later calendar period had a lower excess risk of death. We conclude that transformation resulted in a substantially increased mortality irrespective of MZL subtype compared with the patients without transformation. Our results also suggest a reduction in excess mortality in recent years.

Transformation to diffuse large B‐cell lymphoma and its impact on survival in patients with marginal zone lymphoma: A population‐based study

“…The cumulative incidence of transformation in the current study is lower than previous studies with 5‐year cumulative incidence rates of 2.5% to 15% and 10‐year cumulative incidence rates of 4.7% to 18% 13,14,16‐22 . The difference in the transformation rates between our findings and those of these reports lacks a conclusive cause.…”

Guideline for the diagnosis and management of marginal zone lymphomas: A British Society of Haematology Guideline

“…Population‐based long‐term data on the transformation of MZL is limited; however, in some studies, a cumulative incidence of transformation to aggressive large B‐cell lymphoma of 4.7% at 10 years is described 45 . In this study, the highest risk of transformation was observed in patients with SMZL (14%); a range of 4%–15% is described in other studies 46,47 .…”

A Phase II Study of 131I-rituximab for Patients With Relapsed or Refractory Marginal Zone Lymphoma

“…The 5-year overall survival (OS) rate is approximately 80% after diagnosis. 5 Involved site radiation therapy is currently considered a treatment option for early stage nodal disease or localized EMZL. 6 , 7 In several prospective studies assessing patients with disseminated stage MZL, rituximab-bendamustine, rituximab-cyclophosphamide, vincristine, and prednisolone (CVP) have demonstrated promising efficacy outcomes.…”