Survival rates and patterns of care for patients diagnosed with supratentorial low-grade gliomas: data from the SEER program, 1973-2001

Abstract

Background: Detailed population-based estimates of long-term survival as well as patterns of care for patients with low-grade gliomas examined by age at diagnosis, gender, and race have not been widely available.

Methods: Time to death was examined among 2009 individuals diagnosed with a supratentorial low-grade glioma and reported to the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute from 1973-2001 using Kaplan-Meier estimation. A Cox proportional hazards model was used to assess the effect of age at diagnosis, race, gender, histology, anatomic location within the brain, first course of treatment, and year of diagnosis upon this risk.

Results: The cumulative 5-, 10-, 15- and 20-year survival rates among all individuals initially diagnosed with a supratentorial low-grade glioma were 59.9% (95% confidence interval [95% CI], 57.6-62.2); 42.6% (95% CI, 39.9-45.2); 31.9% (95% CI, 29.0-34.8); and 26.0% (95% CI, 22.7-29.2), respectively. Improved survival was significantly associated with female gender (hazard ratio [HR], 0.84; 95% CI, 0.74-0.95), younger age, white race (HR, 0.70; 95% CI, 0.54-0.93), histology, and later year of diagnosis. Surgical treatment was associated with increased survival. The use of radiation therapy as a first course of treatment for these lesions has significantly decreased over time with the majority of patients receiving only surgery as a first course of treatment.

Conclusions: Data for patients diagnosed with low-grade gliomas revealed increasing survival times over the past 25 years with a subset of patients surviving for decades. Differences in survival by race, gender, histology, and first course of treatment were appreciated. These data suggested that the clinical course of low-grade glioma for some patients may be more encouraging than previously perceived and that the identification of this group of patients may allow refinement of current treatment protocols.