Objectives: Spheno-orbital meningiomas are complex tumours involving the sphenoidal wing, orbit, cavernous sinus, frontal and temporal lobes, have a difficult clinic diagnostic, only when they have symptomatic intracranial tumour or orbitary symptoms. Their complete resection is very difficult or impossible. Evaluation the radiosurgery treatment, that is one of the few effective options those patients have. Surgery is the main treatment for meningioma, but difficult for this localization.

Methods: Between February 2000 and July 2014 we had treated 55 patients and follow up (31 male and 24 females between 29 and 82 years old, median age 61 years old) with Spheno-orbital meningiomas, 29 post-surgery relapse after median time of 30 months (3-230 months), 18 had only partial resection. 88% patients have symptoms at diagnosis. Main clinical symptoms were proptosis, visual disturbance and pain.

We performed MR and CT scans to verify the osseous involvement. The treatment target involves the entire tumour, including the osseous component. The sterotactic procedure has been performed with invasive frame and SRS with linac. The marginal dose we had planned is 15 Gy in 49 cases, 12 Gy in 3 cases, and 3 cases with 10 Gy boost after 40 Gy conventional radiotherapy.

Results: We describe our experience with radiosurgery for relapse, post-operatory treatment or exclusive treatment. All of them included the tumour, affected bone and intraorbitary component for a median volume of 9,22 ml (1,6-30,9 ml). Maximum significant dose to the optic nerve was less than 12 Gy, and less than 8 Gy to the optic chiasm. Median follow up is 74,37 month (7-144 months). Side effects, acute and chronic: 57% had retroocular pain after radiosurgery during 6-18 months. 2 patients had epilepsy episode. 35% show edema in follow up MR, many times asymptomatic. Tumour control with no growing in 97,9%, tumour necrosis and shrinking in 43%, symptoms relieve in 92%. 100% local control in the irradiated volume and the relapses were marginal. 62% of the patients reported clinical improvement.

Conclusions: Radiosurgery is a good and safe treatment for these rare tumours that involve spheno-orbital bone. We had excellent symptoms relief. We have observed very low toxicity, auto limited, and low incidence of side effects and very good tolerance and local control.