Adult intradural intramedullary astrocytomas: a multicenter analysis.

Background: Intramedullary tumors constitute approximately 20-30% of all spinal cord tumors and approximately 30-40% of these are astrocytomas. Furthermore, they comprise only about 2-4% of all primary central nervous system (CNS) tumors. Due to their rarity and poor prognosis, large population-based studies are needed to assess the epidemiology and survival risk factors associated with these tumors in the hope of improving outcomes. The authors undertook this retrospective study to explore factors that may influence survival in adult patients with intramedullary astrocytomas.

Methods: Utilizing the Surveillance, Epidemiology, and End Results (SEER) database, a prospective cancer registry, the authors retrospectively assessed survival in histologically confirmed, intramedullary spinal cord astrocytomas in patients 18 years of age and older. Survival was described with Kaplan-Meier curves and multivariate regression analysis was used to assess the association of several variables with survival while controlling for confounding variables.

Results: Analysis by multivariate regression of 131 cases showed that increasing age of diagnosis [hazard ratio (HR) 1.52, 95% CI: 1.17-1.99, P=0.001], WHO grade IV classification (HR 8.85, 95% CI: 2.83-27.69, P<0.001), tumor invasiveness (HR 2.94, 95% CI: 1.00-8.64, P=0.047), and sub-total resection (HR 5.80, 95% CI: 1.20-28.03, P=0.029) were associated with statistically significant decreases in survival.

Conclusions: This study suggest that older age, higher WHO grade, tumor invasiveness as well as sub-total resection were all associated with a worse prognosis.