Leksell Gamma Knife Therapy for the Treatment of Uveal Melanomas Not Suitable for Brachytherapy

Abstract

Purpose: : To evaluate the effectiveness of Leksell gamma knife treatment for choroidal melanoma not suitable for brachytherapy in terms of tumor control and resulting visual acuity.

Methods: : Retrospective study of patients evaluated for uveal melanoma and found to be poor candidates for brachytherapy due to tumor thickness >10 mm or proximity to optic disc. Patients who chose gamma knife over enucleation were referred for Leksell gamma knife where they received single fraction stereotactic radiation therapy of 20-25 Gy at the 50% isodose line. Follow-up was 2-77 months (mean = 34 months).

Results: : In 11 of 12 (92%) patients, local control was achieved with tumor reduction. 1 patient died from metastatic disease. 3 of 12 (25%) patients had visual acuity better than 20/200 at last follow-up. Loss of visual acuity generally occurred due to radiation complications of therapy which were present in 8 of 12 (67%) patients.

Conclusions: : Patients in this series had high rates of local control (92%) with some patients having preserved visual acuity (25%), despite the size of tumors (2 tumors >10mm thick) or tumor proximity to the optic nerve (7 patients with tumor at or on optic nerve). This suggests that gamma knife is an effective alternative to enucleation in patients with choroidal melanoma who are not candidates for brachytherapy.

Keywords: melanoma