Single-isocenter LINAC radiosurgery proved to be an effective treatment for acoustic neuromas in this series, with results that were comparable with those reported for gamma knife radiosurgery and multiple isocenters.

One hundred and seventeen patients with cavernous sinus meningiomas had LINAC radiosurgery at our institution in the period 1993-2007. Six cases were lost and 9 had less than 1 year follow up. The remaining 102 patients were prospectively followed up at 1 y intervals with clinical, neuro-ophthalmological and MRI examinations. Patients' age ranged between 31 and 86 years (mean 57). Seventy percent were females. The mean tumor volume was 7 cc. Thirty-three patients had previous microsurgery. Tumors were defined with high resolution MRI obtained 1-2 days before treatment and fused to stereotactic CT. Treatment was mostly delivered through a minimultileaf collimator and multiple dynamic arcs. The minimal dose to the tumor margin was 12-17.5 Gy (mean 13.5) encompassed by the 80% isodose shell. Radiation dose to the optic apparatus was kept below 10 Gy. Follow up ranged from 12 to 180 months (mean 67 months). Tumor control (lack of growth) was 98% (58% of the tumors reduced their volumes). Sixty-four patients presented with cranial nerve deficit. Thirty-nine percent improved or resolved following radiosurgery. Cranial neuropathy had significantly higher resolution rates when radiosurgery was performed early (<1 year) after its appearance (53% as opposed to 26%) even in patients with deficits post surgery. Complications were seen in five patients (1 with deafferentation pain, 1 with facial hypesthesia, 1 with visual loss and 2 with partial VI neuropathy). Radiosurgery had a high control rate for meningiomas of the cavernous sinus with few and mild complications. Cranial neuropathy can be solved by treatment, particularly those of recent onset.

This study indicates that linear accelerator radiosurgery can achieve a high control rate of meningiomas involving the cavernous sinus with no mortality and a low incidence of morbidity.

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