31 Uveal Melanoma

Uveal Melanoma

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THE GEC ESTROHANDBOOKOF BRACHYTHERAPY | Part II Clinical Practice Version 1 - 15/04/2020

and endothelial cells, with a delayed onset after irradiation and usually leads to irreversible visual impairment. The earliest clinicalmanifestationof radiation retinopathy is generally macular oedema. Subsequent ophthalmoscopic and angiographic features include capillary nonperfusion, microaneurysms, retinal hemorrhages, intraretinal exudation, nerve fibre layer infarcts, perivascular sheathing and retinal or optic disc neovascularization. Different treatment modalities have been used in the management of radiation retinopathy. These include laser photocoagulation, photodynamic therapy, corticosteroids and anti-vascular endothelial growth factor (anti-VEGF) agents. Several studies have reported promising results with the use of anti-VEGF agents in the treatment of radiation-induced macular oedema and retinal neovascularization, although the optimal treatment regime has yet to be defined. There is a complex interplay of different factors that influence the toxicity from brachytherapy. Until now there exists no comprehensive staging system for the ophthalmic side effects of radiation therapy and no published prospective randomized or large-scale studies which have examined the effects relative to initial radiation dose, dose rate or source. Established, successful long-termmanagement strategies for this condition are lacking. Most of the current therapies have been copied from the treatment of other ischaemic retinopathies especially diabetic retinopathy. However, the vascular damage observed in RR occurs at the level of the endothelial cells, while in diabetes the damage occurs mainly at the level of the pericytes, which may explain the poor results obtained in the treatment of RR. Recent efforts have been directed towards prevention of radiation retinopathy rather than treatment after signs that radiation damage have already occurred. (ABS2014) Shah et all demonstrated that intravitreal bevacizumab injection at plaque removal and every 4 months following plaque could reduce rates of macular edema and poor visual acuity 2 years after plaque brachytherapy. The goal is to identify the patients at risk to develop radiationmaculopathy, using graphical calculating devices such as a nomogram, and to select them for preventive treatment. Optic neuropathy is most likely to develop if the dose received by optic nerve exceeds 50 Gy; the incidence reported varies between 2.2 and 29.4% by 5 years after plaque. This complication occurs as a result of direct neuropathic effects and because of radiation- induced vasculopathy. It is associated with significant visual loss. Secondary glaucoma is one of the most severe findings among radiation-related side effects. Increased incidence of secondary glaucoma is associated with greater tumour thickness and it has been shown to be the most frequent reason along with local recurrence for secondary enucleation. Loss of Visual Function The COMS Group provided initial evidence for preservation of visual acuity in patients treated with episcleral brachytherapy. Three years after treatment, 49% of eyes treated demonstrated significant loss of visual acuity, defined as loss of six lines or more from baseline, with 43% demonstrating vision of 20/200 or worse.

Useful vision can be preserved in the majority of patients, if the tumour is not located too near the macula or the optic nerve, or if it is not too large. Long term radiation-relatedmorbidity is strongly correlated with the tumour site and the corresponding position of the plaque. It is most pronounced in large tumours near the macula or the optic disc with degeneration or destruction of the macula and atrophy of the optic nerve.