Survival outcomes in marginal zone lymphomas in the rituximab era: Analysis of the Surveillance, Epidemiology, and End Results (SEER) database.

Abstract

8045 Background: Despite prognostic models developed for marginal zone lymphoma (MZL), the impact of different characteristics and treatments on survival in the population is largely unknown. We studied survival of MZL patients included in the SEER database. Methods: Records of MZL adult cases diagnosed between 1989-2008 were studied using descriptive methods and analysis of overall (OS) and lymphoma-specific (LSS) survival based on Kaplan-Meier function, stratified log-rank tests and Cox proportional hazard models. Results: 13,957 patients with MZL were identified and classified as splenic (SMZL; n=1,111, 8%), nodal (NMZL; n=4,101, 29%) or extranodal MALT-type MZL (MALT; n=8,745, 63%). The median age was 68 years, 74% of patients were white and 55% were women. Median follow-up was 40 months. MALT was more common in non-Caucasians (p<10-27). B-symptoms were more common in SMZL (p<10-5). Both LSS and OS were significantly better for MALT (p<10-60) with no difference between SMZL and NZML (p=0.30). 10-year LSS estimates were 67% for SMZL, 67% for NMZL, 84% for MALT. There was evidence for improved LSS since 2000 in MALT (HR 0.69, 95% CI 0.59-0.82, p=0.0003) and NMZL (HR 0.64, 95% CI 0.54-0.77, p<10-5), but not for SMZL (HR 0.85, 95% CI 0.56-1.28, p=0.43). Similar results were found for OS. There were differences in survival in MALT subtypes depending on primary site (p<10-12; Table). Conclusions: In the rituximab era, survival has improved for MALT and NMZL, but not for SMZL, possibly due to disparate treatment paradigms. The prognosis of MALT is different depending on primary site of involvement. [Table: see text]