Alderuccio JP, et al. - In a large cohort of patients with marginal zone lymphoma (MZL), researchers investigated risk factors for higher-grade transformation (HGT) to aggressive lymphoma and its influence on overall survival (OS). The factors that mainly predicted an increased risk of HGT were failure to achieve complete remission (CR) after initial treatment, elevated lactate dehydrogenase, and more than four nodal sites at the time of MZL diagnosis. Shorter OS was seen in patients with HGT.

Methods

• A total of 453 patients with biopsy-proven MZL seen at researchers' institution between 1995 and 2016 were included.
• Analyses of time-to-event outcomes were performed by using Kaplan-Meier, Cox proportional hazards regression, and competing risk methods.

Results

• Biopsy-proven HGT to diffuse large B-cell lymphoma was seen in 34 patients (7.5%), including seven (21%) diagnosed at the time of initial MZL diagnosis.
• Findings showed that, 29 months (range, 1.3 to 135 months) was the median time to HGT among 27 incident patients.
• Those with nodal/splenic MZL (subdistribution hazard ratio [SHR], 2.60; P=.023) had a higher risk of HGT.
• Factors that conveyed significantly higher risk for HGT (P < .02) on multivariable competing risk analysis were elevated lactate dehydrogenase (SHR, 2.71), more than four nodal sites (SHR, 2.97), and failure to achieve complete remission (CR) after initial treatment (SHR, 3.76).
• International Prognostic Index (IPI), Follicular Lymphoma IPI, and Mucosa-Associated Lymphoid Tissue Lymphoma IPI were identified to be the only significant predictors of HGT univariably.
• Shorter OS (5-year rate, 65% v 86%; P < .001) was seen in patients with HGT.
• Shorter OS was observed in patients who presented with HGT within 12 months of MZL diagnosis vs those with HGT at MZL diagnosis combined with those with HGT more than 12 months later (4-year rate, 43% v 81%, P < .001).
• The primary significant factors that predicted shorter progression-free survival and OS were non-CR and higher scores of IPI, follicular lymphoma IPI, and mucosa-associated lymphoid tissue lymphoma IPI.