Pilocytic astrocytoma survival in adults: analysis of the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute

Abstract

Pilocytic astrocytoma is a WHO grade 1 brain tumor common in children. Relatively little is known about the behavior of pilocytic astrocytomas in adult patients, largely due to the rarity of pilocytic astrocytoma in this population. Some data suggest that adults share the excellent prognosis seen in children, while other reports suggest more aggressive tumor behavior in adult patients. Patients diagnosed with pilocytic astrocytoma between 1973 and 2008 were identified in the National Cancer Institute Surveillance, Epidemiology, and End Results Program database. Age-group specific survival was analyzed with overall, expected, and cancer-specific survival rates. Further survival analyses were performed with the Kaplan-Meier method and Cox Proportional Hazards models. 3,066 patients with pilocytic astrocytoma were identified, including 865 patients aged 20 years and older. Survival rates declined significantly with age, from 96.5% 60-month survival in patients 5-19 years (95% CI 95.3-97.4) to 52.9% 60-month survival in adult patients 60+ years of age (95% CI 38.4-65.5), with a corresponding decrease in relative and cancer-specific survival rates. Gross total resection was a positive prognostic indicator in adults, while patients receiving radiation had shorter survival regardless of extent of resection. Pilocytic astrocytoma is associated with higher mortality in adult patients than in children and teens, and survival decreases with increasing age in adults. The morbidity of pilocytic astrocytoma in adults provides rationale for future trials of adjuvant treatment in high-risk patients.