Gamma knife radiosurgery for uveal melanoma ineligible for brachytherapy by the Collaborative Ocular Melanoma Study criteria

Nicola G Ghazi¹, Christopher S Ketcherside¹, Jason Sheehan², Brian P Conway¹

¹Department of Ophthalmology and ²Neurosurgery, University of Virginia Health System, Charlottesville, VA, USA

Purpose: To report outcomes of Gamma Knife radiosurgery (GKRS) in treating uveal melanoma lesions ineligible for standard brachytherapy.

Methods: A retrospective interventional case series of uveal melanoma patients treated with GKRS between 1996 and 2004 was performed. The main outcome measures were local tumor control, metastasis, and death.

Results: Four patients with uveal melanoma treated with GKS were identified. Three tumors involved the ciliary body and one was macular with its border within 2 mm of the optic disc. Adequate globe stabilization was achieved by retrobulbar anesthesia in all cases. Pretreatment mean visual acuity was 20/30. Tumor volume as determined by magnetic resonance imaging ranged from 0.05 to 0.30 cc. Ultrasonographic greatest tumor diameter and height ranged from 11 to 18 mm (mean 14.5 mm) and 2.9 to 4.5 mm (mean 3.6 mm), respectively. The peripheral dose varied from 16.5 to 30 Gray. Local tumor control was achieved in all cases over a follow up period of 6 to 96 months. Mean final visual acuity was 20/50. One eye was enucleated for neovascular glaucoma and one patient died from liver and lung metastasis.

Conclusions: GKRS for uveal melanoma appears to be safe and effective. The metastasis and mortality rates appear to be comparable to those following brachytherapy and enucleation. Moreover, local tumor control and enucleation rates are similar to those following brachytherapy. The findings in this small series suggest a role for GKRS in the treatment of selected cases of uveal melanomas.

Keywords: gamma knife radiosurgery, radiation therapy, uveal melanoma