Gamma Knife Stereotactic Radiosurgery for the Treatment of Primary and Metastatic Ocular Malignancies

Background: Gamma knife radiosurgery (GKR) can be used for precise targeting of malignant lesions of the CNS when brachytherapy is not an appropriate option. Objectives: This study reports treatment technique, efficacy, and radiation-induced adverse effects in patients with primary and metastatic ocular lesions treated with Leksell GKR. Methods: A retrospective, single-institution review was conducted of 28 patients with primary or metastatic ocular disease, treated from 2000 to 2014. The dose to margin was 17-27 Gy (maximum dose 28-54 Gy). Primary outcomes included overall survival (OS), local control, progression-free survival (PFS), and enucleation. Results: The median age at diagnosis was 70 years, and the median follow-up was 26.4 months. Of the 28 patients, 11 (39%) had metastatic ocular disease, and 17 (61%) were diagnosed with primary ocular melanoma (stage T2a-T4e). The average maximum dose and dose to margin were 41 and 21 Gy, respectively. The mean dose to the optic nerve was 12.6 Gy. The 5-year OS was 46% (95% CI: 23.6-68.4%) for the entire cohort; the 5-year PFS for M0 patients who presented with primary ocular melanoma lesions was 90% (95% CI: 71-100%). Only 1 patient required enucleation after radiation treatment. Conclusion: GKR is an effective option, with acceptable levels of toxicity, in the treatment of primary and metastatic ocular lesions.