Increasing incidence of primary central nervous system lymphoma but no improvement in survival in Sweden 2000-2013

Abstract

Objectives: This study aims to characterize the epidemiology of immunocompetent Primary central nervous system lymphoma (PCNSL) diagnosed 2000-2013 in Sweden.

Methods: Cases were identified in the population-based Swedish Lymphoma Register. Incidence per 100 000 person-years and 95% confidence intervals (CI) were calculated, and PCNSL-specific survival was estimated using relative survival. Tests for temporal trends were performed using Poisson regression. Population incidence of all brain tumors was retrieved for comparison.

Results: With 359 identified PCNSL cases (median age 66 years), overall incidence was 0.26 (95% CI: 0.24-0.29) and the average annual increase 4% (P = .002). The increasing trend was primarily observed among elderly individuals (70+ years). Similarly, an increase in incidence of all brain tumors was noted only among the elderly. There was no significant improvement in relative survival across the study period although, among fit patients (with Eastern Cooperative Oncology Group, EGOC 0), survival plateaued 6 years after diagnosis.

Conclusion: The increasing PCNSL incidence in the elderly was consistent with an increasing incidence of brain tumors of any type and may in part be attributable to improved diagnostics and reporting in this group. New treatment options have not yet translated into general survival improvements in a population-based setting, although the presence of long-term survivors among fit patients is encouraging.

Keywords: central nervous system neoplasms; epidemiology; incidence; lymphoma; survival.