Short-term Effect of Gamma Knife Radiosurgery for a Choroidal Tumor

Abstract

Purpose: To evaluate the effectiveness and safety of treating choroidal melanoma and cancer that has metastasized to the choroid with gamma knife radiosurgery (GKR). Methods: We performed a retrospective chart review that included 10 eyes of eight patients with a diagnosis of choroidal tumors who underwent GKR between January 2016 and February 2019 and who had at least one month follow-up visit. Results: The mean patient age was 57.9 +/- 14.6 years (range, 32-83 years). The choroidal tumor group included six choroidal metastases and four choroidal melanomas. The mean follow-up period after GKR was 7.0 +/- 4.3 months (range, 2-13 months). The mean cumulative marginal dose was 25.36 +/- 7.35 Gy (range, 16-45 Gy). Pre- and postoperative magnetic resonance imaging revealed a reduction in tumor volume in eight of the 10 eyes and five of them presented with improved visual symptoms. One patient showed increased tumor volume; however, a new choroidal lesion was not observed. Another patient showed no reduction in tumor size; however, the pain had worsened, and the eye was enucleated. The mean maximum tumor diameter decreased from 1.60 +/- 0.37 cm before to 1.22 +/- 0.47 cm after GKR (p = 0.004), and the mean minimum diameter decreased from 0.62 +/- 0.27 cm before to 0.38 +/- 0.35 cm after GKR (p = 0.031). No radiation-induced optic neuropathy, retinopathy, or cataracts was observed in any of the cases during the follow-up period. Conclusions: GKR was shown to be safe for choroidal lesions identified in orbital magnetic resonance imaging with a reduction in the size of choroidal tumors and eyeball preservation expected with this treatment approach.