Radiosurgery for cranial base chordomas and chondrosarcomas

OBJECTIVE: To evaluate the efficacy and toxicity of radiosurgery in the treatment of cranial base chordoma and chondrosarcoma. METHODS: We reviewed 29 patients with cranial base chordoma (n = 25) or chondrosarcoma (n = 4) who underwent stereotactic radiosurgery between September 1990 and December 2002. The median patient age was 45 years (range, 10-81 yr). Nineteen patients also had radiation therapy before or in conjunction with radiosurgery (median dose, 50.4 Gy). The median tumor volume was 14.4 cm³ (range, 0.6-65.1 cm³). The median tumor margin dose was 15 Gy (range, 10-20 Gy); the median maximum radiation dose was 30 Gy (range, 20-40 Gy). Median clinical and imaging follow-up periods were 4.8 and 4.5 years, respectively. RESULTS: Seven chordoma patients (28%) had tumor progression (in-field, n = 3; out-of-field, n = 4), whereas 18 had stable disease or tumor shrinkage. No patient with a chondroid chordoma had tumor enlargement. The actuarial tumor control rates were 89 and 32% at 2 and 5 years, respectively. All 4 patients with chondrosarcoma had tumor control. Clinically, 7 patients (24%) had improvement of pretreatment symptoms, 16 (55%) remained stable, and 6 (21%) worsened. Three patients with tumor progression died. Ten patients (34%) had radiation-related complications. Complications included cranial nerve deficits (n = 6), radiation necrosis (n = 5), and pituitary dysfunction (n = 3). Patients having radiosurgery alone had no toxicity. CONCLUSION: Cranial base chordomas and chondrosarcomas remain a formidable management challenge. Radiosurgery as an adjunct to surgical resection provides in-field tumor control for some patients, but radiation-related complications are relatively high, especially when radiosurgery is combined with fractionated radiation therapy.