Stereotactic radiosurgery for intracranial chondrosarcoma.

To assess outcomes after stereotactic radiosurgery (SRS) for chondrosarcomas of the skull base, we reviewed 22 patients with cranial base chondrosarcomas who underwent SRS between 1987 and 2009. The median patient age was 42 years (range, 15-75). The median SRS target volume was 8.0 cc (range, 0.9-28.2) and median margin dose was 15.0 Gy (range, 10.5-20). 15 patients (68 %) underwent one or more tumor resections and 3 of these patients also had fractionated radiation therapy. At a median follow-up of 75 months after SRS, seven patients died due to tumor progression. The actuarial overall survival after SRS for the entire group of chondrosarcoma patients was 95, 76, 70 and 56 % at 1, 3, 5 and 10 years, respectively. Factors associated with longer survival after SRS included patient age >40 years, a shorter interval (<6 months) between diagnosis and SRS, and either no or a single prior resection. Treated tumor control rates were 91, 72, 72 and 54 % at 1, 3, 5 and 10 years, respectively. Factors associated with longer progression-free survival after SRS included patient age >40 years and no prior RT. Symptomatic adverse radiation effects occurred in two patients (10 %). Stereotactic radiosurgery may provide a benefit to patients as either a primary or adjuvant therapy. The ability to achieve tumor control in patients with chondrosarcoma is likely to be enhanced by earlier timing of SRS after diagnosis and multimodal management, beginning with resection when feasible followed by early SRS for progressive residual tumor.