Purpose: Skull base chordomas and chondrosarcomas pose management challenges owing to their critical location, locally aggressive nature, and high recurrence rate despite multimodality treatment. We used stereotactic radiosurgery as primary or adjuvant therapy to achieve safe and effective therapeutic irradiation.
Methods and materials: At an average of 4 years (range 1-7), we evaluated 15 patients (nine with chordomas and six with chondrosarcomas) who had gamma-knife radiosurgery as an adjunct (13 patients) or as an alternative to microsurgical resection (two patients). Patient age varied from 7 to 70 years (mean 38). There was a distinct male preponderance (2:1). Thirteen patients had undergone between one and four resections. Using conformal radiosurgical planning, a maximum tumor dose of 24-40 Gy (mean 36) and a tumor margin dose of 12-20 Gy (mean 18) was given to a mean tumor volume of 4.6 ml.
Results: Eight patients showed clinical improvement, three remained stable, and four died. Two of the four patients who died had tumor progression remote from the radiosurgery volume; two patients died of unrelated disorders. Among 11 surviving patients, follow-up imaging showed a reduction in tumor size in five, no further tumor growth in five, and an increase in the size of the tumor in one. The patient with further tumor growth after radiosurgery subsequently underwent repeat resection.
Conclusion: Despite the formidable management challenge posed by these neoplasms, our long-term evaluation has shown that radiosurgery is a safe and effective treatment for patients with small volume tumors.