Review of Patients With Brain Metastasis Treated With Fractionated Stereotactic Radiation Therapy to Surgical Resection Cavity

Abstract

common despite maximal surgical resection and high-dose radiation therapy (RT). The aim of this study was to assess the evolving role of RT and its effect on survival outcomes of skull base chordoma over the past two decades. Materials/Methods: Using the Surveillance, Epidemiology, and End Results (SEER) database, we included all adult patients with chordoma, chondroid or dedifferentiated chordoma, or chondrosarcoma located in the bones of the skull or face diagnosed from 1988 to 2008. The chi-square test and logistic regression were used to identify predictors of gross total resection (GTR) and/or RT utilization. Cox proportional hazards modeling was used to identify predictors of overall survival. Results: The analysis included 376 adult patients, including 182 (48%) with chordoma NOS, 20 (5%) with chondroid or dedifferentiated chordoma, and 175 (46%) with chondrosarcoma. Among the 214 patients (57%) who underwent surgical resection, 89 (42%) received GTR, 108 (50%) received subtotal resection, and 17 (8%) received resection of unknown extent. RT was utilized in 170 patients (46%) overall, among whom RT was used as adjuvant therapy in 148 (87%). Utilization of GTR and RT was not significantly different by age, sex, race, diagnosis year, or histology on univariate analysis, except for a higher median age for patients receiving RT (49 vs. 43 years, p Z 0.012). Independent predictors of higher utilization of gross total resection on logistic regression included age <65 (OR 2.68, p Z 0.014) and diagnosis year prior to 2001 (OR 1.79, p Z 0.046), while the only independent predictor of higher utilization of RT included age 65 (OR 1.82, p Z 0.032). Independent predictors of improved overall survival on Cox proportional hazards analysis included age <65 (HR 0.25, p < 0.001), diagnosis year after 2001 (HR 0.44, p Z 0.004), and chondrosarcoma histology (HR 0.42, p Z 0.001), but not surgical extent or RT utilization. Conclusions: On a national scale, survival from skull base chordoma and chondrosarcoma appears to have improved significantly over time, though rates of surgical resection and RT have not increased over time. Although no association was observed between RT utilization and improved survival, this may be due to confounding, since RT may be more likely to be delivered to patients with more aggressive disease and poorer prognosis based on unmeasured variables. Author Disclosure: H. Park: None. K.B. Roberts: None. J.B. Yu: None.