LINAC radiosurgery for cavernous sinus meningiomas.

Radiosurgery is increasingly used to treat unresectable cavernous sinus tumors. Since 1989, 24 patients with cavernous sinus meningiomas have been treated at Stanford University Medical Center with linear accelerator (LINAC) radiosurgery. The mean age of the patients was 47.8 years (range 28-78). The mean volume treated was 6. 83 cm3 (range 0.45-22.45 cm3), covered with an average of 2.3 isocenters (range 1-5). Radiation dose averaged 17.7 Gy (range 14-20 Gy). This group of patients was retrospectively studied by sending clinical questionnaires to both the patient/family and referring physicians, and reviewing clinic charts. In addition, follow-up imaging studies were obtained to measure residual tumor volume. Follow-up averaged 45.6 months (range 19-80). Tumor control (stabilization) following radiosurgery was noted in 15 (63%) and tumor shrinkage in 9 (37%). Seven meningiomas (29%) showed evidence of central tumor necrosis on MRI imaging 1-3 years after radiosurgery. Neurologic status was improved in 10 patients (42%) and unchanged in 12 patients (50%). There was 1 case of symptomatic brain necrosis and 1 case of radiation edema (asymptomatic). All other complications were transient, including 4 cases of trigeminal hypesthesia and 1 case of worsening diplopia. The 2-year actuarial tumor control rate was 100%. Although follow-up is still short, this experience corroborates prior reports that radiosurgery can be used to treat selected small cavernous sinus meningiomas with good to excellent clinical results and minimal morbidity.