For 40 years, a certain subset of brain tumor patients have undergone iodine-125 brachytherapy for local tumor control and, while it isn’t a cure-all, it has helped many.1 Among its known complications, the literature shows a number of serious issues, including an increase in intracranial pressure, severe edema, cerebral artery occlusion and intracranial hemorrhaging.1 A new study in the Journal of Glaucoma identifies yet another one: glaucoma.2

According to investigators, the treatments are associated with the development of both secondary open-angle glaucoma and neovascular glaucoma in patients with uveal melanoma. This risk, the study shows, is substantial.2

The study looked at 374 eyes of patients diagnosed with uveal melanoma and treated with iodine-125 brachytherapy. The researchers checked the patients’ IOPs and examined them under gonioscopy. In total, 8.6% of them were diagnosed with open-angle glaucoma and an additional 6.7% developed neovascular glaucoma.

The study was able to pin down multivariate risk factors for developing secondary open-angle glaucoma: older age, greater tumor size, iris location of uveal melanoma, higher baseline IOP, ciliary body involvement and eyes having undergone combined brachytherapy with vitrectomy and silicone oil placement for radiation attenuation. The risk factors for neovascular glaucoma included greater tumor size, greater number of pack-years smoking history, pseudophakia and higher grade of radiation retinopathy severity by fluorescein angiogram.

Close ophthalmic monitoring of patients is necessary for detection and timely treatment of glaucoma to maximize visual outcome, the researchers concluded in their paper.

1. Schwarz S, Thon N, Nikolajek K, et al. Iodine-125 brachytherapy for brain tumours - a review. Radiat Oncol. 2012;7:30.

2. Kim E, Salazar D, McCannel C, et al. Glaucoma after Iodine 125 Brachytherapy for Uveal Melanoma. J Glacuoma. November 1, 2019. [Epub ahead of print].