Gamma Knife Radiosurgery for Orbital Lesions

ABSTRACT

PURPOSE: To evaluate the effectiveness and safety of treating orbital lesions with gamma knife radiosurgery (GKS). METHODS: Between April 2004 and January 2006, ten patients who had orbital tumors or vascular lesions and who underwent GKS were included in this retrospective study. RESULTS: Ten patients with orbital lesions were treated with GKS. The group of orbital lesions consisted of 5 meningiomas, 2 schwannomas, 1 cavernous hemangioma, 1 arteriovenous fistula, and 1 adenoidcystic carcinoma of the lacrimal gland. The most common symptom was proptosis. The tumors were located at the orbital apex in eight patients, and five of these patients were treated with fractionated stereotactic radiosurgery. The mean cumulative marginal dose was 17.0 Gy (12-20 Gy), and the mean cumulative maximal dose was 30.8 Gy (16.2-40.4 Gy). The follow-up period ranged from 3 to 25 months (mean 13.9 months). During the follow-up period, magnetic resonance imaging revealed a decrease of tumor volume in 3 patients with symptomatic improvement. In two patients, tumor volume increased. No radiation-induced optic neuropathy, retinopathy, or cataract was observed in any of the 10 patients during the follow-up period. CONCLUSIONS: Gamma knife radiosurgery is an effective and relatively safe treatment when orbital lesions have a high risk of neurosurgical deficits with surgery, when they recur after incomplete resection, or when complete removal of tumor is impossible.