In a large retrospective study, investigators demonstrated that the risk of histologic transformation (HT) appeared lower than for follicular lymphoma, according to an article published online ahead of print in the Annals of Oncology.1
HT is poorly understood in patients with marginal zone lymphoma (MZL). Investigators sought to analyze incidence and risk factors for HT in a large series of patients with MZL.
A total of 340 patients with MZL diagnosed and treated between 1995 and 2012 were included in the study. One hundred fifty-seven patients had extranodal MZL (MALT lymphoma 46%), 85 patients had splenic MZL (SMZL, 25%), and 37 patients had nodal MZL (NMZL, 11%); 61 patients (18%) had bone marrow infiltration at presentation, with or without detectable involvement of peripheral blood, but without other involved sites. These were considered clonal B-cell lymphocytosis of marginal zone origin (CBL-MZ).
At a median follow-up of 4.8 years, results showed the median overall and progression-free survival of the whole population were 14.5 years and 5 years. HT was observed in 13 cases (3.8%, 95% CI: 2-6.5).
Elevated lactate dehydrogenase (LDH) at diagnosis was associated with risk of HT (P=0.019). HT occurred in 5% of SMZL, 4% of MALT lymphomas, 3% of NMZL, and 3% of CBL-MZ (P=0.974). Risk of HT was 5% (95% CI: 3%-9%) at 5 and 10 years after diagnosis and 10% (95% CI: 5%-20%) at 12 years.
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At HT, most patients most patients had high LDH and presence of B symptoms. At a median follow-up of 12 months following HT, 4 of 13 patients died, all from lymphoma-related causes, with a 2-year post-transformation survival rate of 57% (95% CI: 13%-86%).
- Conconi A, Franceschetti S, von Hohenstaufen A, et al. Histologic transformation in marginal zone lymphomas. [published online ahead of print September 23, 2015]. Ann Oncol. doi: 10.1093/annonc/mdv368.