Trends in survival from primary central nervous system lymphoma, 1975-1999: a population-based analysis

The age-adjusted incidence of primary central nervous system lymphoma (PCNSL) has increased since the 1970s, and treatment for this disease has evolved considerably. The objective of this study was to examine time trends in overall survival and disease-specific mortality in a population-based cohort of patients with PCNSL.

We identified patients diagnosed with PCNSL from 1975-1999 in the Surveillance, Epidemiology, and End Results (SEER) cancer registries. To assess time trends, year of diagnosis was classified in 5-year intervals: 1975-1980, 1981-1985, 1986-1990, 1991-1995, and 1996-1999. Overall survival distributions were estimated via Kaplan-Meier methodology and a competing risk analysis was used to assess PCNSL-specific mortality. We used information on underlying cause of death to distinguish likely immunocompetent patients from those whose PCNSL was related to human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS). We also examined survival stratified by age at diagnosis.

From 1975-1999, 2462 patients were diagnosed with PCNSL in SEER. Median survival was 4 months (95% CI 4, 5) for the entire cohort and 9 months (95% CI 8, 11) for the immunocompetent cohort (n = 1565). In the immunocompetent cohort, 965 of 1323 (73%) deaths were attributed to PCNSL. No significant time trend was observed in either overall or PCNSL-specific survival.

Overall survival for patients with PCNSL has not improved consistently in the past three decades despite important therapeutic advances during this time. Although results from clinical trials suggest progress in the treatment of PCNSL, survival improvements are not reflected in this population-based cohort.