Outcomes and patterns of care in adult skull base chondrosarcomas from the SEER database

This study aims to demonstrate survival rates and treatment patterns among patients with chondrosarcomas of the skull base using a large population database. Patients with skull base chondrosarcomas between 1973 and 2009 were identified from the USA Surveillance, Epidemiology, and End Results (SEER) database. Kaplan-Meier survival analysis was used to examine the effect of surgery and radiation on overall survival. We identified 226 patients with skull base chondrosarcomas. Median follow-up was 5.4 years. Median overall survival was 22 years, and 10 year survival was 68.2%. Most patients underwent surgery (92.5%). Few received radiation after diagnosis (38.1%). Ten year survival for all patients treated with surgery was significantly increased compared to those without surgery (69.3% versus 53.9%, p=0.02). There was a significant difference in survival amongst treatment groups (p=0.02), with median overall survival not yet reached for patients who received surgery and radiation (median follow-up 5.3 years), compared to 22 years for non-irradiated surgical patients. Surgery predicted better overall survival by univariate analysis (hazard ratio [HR] 0.420, p=0.03). Female sex (HR 0.470, p=0.011), younger age at diagnosis (HR 1.046, p<0.0001), and later year of diagnosis (HR 0.949, p=0.0006) were prognostic of improved survival in a multivariate model. In subgroup analysis of patients with documented tumor size, smaller tumor size (HR 1.054, p=0.0003) and younger age (HR 1.021, p=0.0067) predicted improved survival. This population based study further reaffirms the role of surgery as an effective treatment for skull base chondrosarcoma as previously reported in small case series. Adjuvant radiation may also confer survival benefit. Optimal treatment strategy has yet to be defined in the literature.