Patient with choroidal melanoma presents with additional retinal findings
A 55-year-old white female presented to our clinics for a comprehensive eye examination. Her ocular history was significant for a choroidal nevus in the right eye and a choroidal melanoma in the left eye, which had been treated and was being followed by an ocular oncologist. Her medical history was significant for hypothyroidism since 1991, for which she was taking levothyroxine.
Ocular examination revealed best-corrected visual acuity of 20/20 OD and 20/400 OS. There was no improvement on pinhole testing in the left eye. Pupils were equal with a grade 1 afferent pupillary defect in the left eye. Ocular motilities were unremarkable in both eyes. Confrontation visual fields were unremarkable in the right eye but showed moderate defect in the left eye.
Sherrol A. Reynolds
Slit-lamp evaluation was unremarkable. Intraocular pressures were 12 mm Hg OD and OS. Examination of the retina revealed a large choroidal nevus in the right eye. A significant area of retinal edema with circinate exudates, blot hemorrhages, microaneurysms, fibrosis and neovascularization of the posterior pole was noted in the left eye.
Images: Reynolds S
What’s your diagnosis?
The retinal finding in the left eye may be diabetic retinopathy, hypertensive retinopathy, retinal vascular occlusion, systemic vasculitides, acquired telangiectasia or radiation retinopathy.
Upon further questioning, the patient reported a history of having multiple anti-vascular endothelial growth factor (anti-VEGF) injections post plaque brachytherapy radiation treatment of the choroidal melanoma 9 years ago. Based on the additional information, the clinical characteristic and location of the retinal changes, it was more likely the patient had radiation retinopathy in her left eye. The presence of a large nevus in the fellow eye required close monitoring.
Radiation therapy has a crucial role in the treatment of various disease processes and, similar to other therapeutics, sight-limiting side effects can occur. Secondary complications of radiotherapy can lead to keratopathy, cataract, glaucoma and radiation retinopathy.
Radiation retinopathy, first described by Stallard in 1933, occurs after exposure to any type of radiation. It can be divided into nonproliferative, proliferative and maculopathy. The presence of microaneurysms, hemorrhages, cotton-wool spots, hard exudates, retinal edema and/or vascular sheathing constitutes nonproliferative changes. Proliferative retinopathy is observed when retinal or disc neovascularization, vitreous hemorrhage or retinal detachment occurs. The presence of macular edema, as in this case, is the leading cause of vision loss.
Although not clearly understood, it is believed that exposure to radiation causes endothelial cell loss and capillary closure leading to an occlusive microangiography, according to Archer and colleagues. These findings are typically observed in the posterior pole of the retina, which is more sensitive to radiation, purportedly due to the increased number of capillaries and higher blood flow than the peripheral retina, Zamber and Kinyoun reported.
Radiation retinopathy is a common complication after external-beam radiation of the eye, orbit, eyelids, face, paranasal sinuses, nasopharynx and brain, as well as plaque brachytherapy. Our patient was treated with plaque brachytherapy, a common treatment for choroidal melanoma, and subsequently developed proliferative radiation retinopathy. Stack and colleagues reported that after plaque brachytherapy for choroidal melanoma, radiation retinopathy involving the macula occurs in 10% to 63% of eyes.
It may take months to years after radiation treatment to develop radiation retinopathy. The key determinants in the development of radiation retinopathy are the total dose of radiation administered to the retina, the size and location of the tumor as well as its response to radiation. The Collaborative Ocular Melanoma Study found that radiation retinopathy was seen in 90.7% of eyes 8 years after iodine 125 brachytherapy for choroidal melanoma (Boldt and colleagues).
Patients may be asymptomatic if the retinopathy is mild, while those with advanced disease, as in our patient, can present with vision loss or floaters. Concomitant diseases such as diabetes, hypertension, collagen-vascular disease and concurrent chemotherapy are additional risk factors for the development of retinopathy and can exacerbate the retinal changes.
Differential diagnosis, treatment
The differential diagnoses for radiation retinopathy appear in the accompanying table. Because radiation retinopathy is similar to diabetic retinopathy, it may be difficult to decide the exact nature of the retinopathy. A careful history of radiotherapy and monocular status may assist in the differential diagnosis.
In rare instances, spontaneous improvement can occur. While currently no guidelines exist for radiation retinopathy, prompt treatment is essential to prevent irreversible visual loss. A recent classification has been devised by Finger and Kurli that describes stages of radiation retinopathy in relation to the clinical signs seen, symptoms, location, best method of visualization and the risk of vision loss, which may assist with determining the prognosis.
Various treatment options include intravitreal bevacizumab, intravitreal triamcinolone acetonide and laser photocoagulation, with a few case reports describing other methods, including hyperbaric oxygen, administration of pentoxifylline and photodynamic therapy (PDT).
Management for this patient
Our patient was treated with multiple anti-VEGF injections. Variable success rates on the effectiveness of both anti-VEGF and intravitreal triamcinolone acetonide in treating radiation retinopathy have been published. Early panretinal photocoagulation has been advocated in inducing regression of radiation retinopathy. Early diagnosis of radiation retinopathy with spectral domain optical coherence tomography has also been shown to respond to laser photocoagulation, especially in high risk cases.
Other approaches for treating radiation retinopathy, including PDT, hyperbaric oxygen treatment and oral pentoxifylline have been reported (Finger, Lee and colleagues, Gall and colleagues). Small studies have shown regression of radiation retinopathy after PDT. Hyperbaric oxygen treatment, which improves oxygenation and hypothetically counteracts the ischemia of radiation retinopathy and neuropathy, has been used in one reported case. Pentoxifylline, a drug commonly used to treat peripheral vascular disease, has also been used to treat radiation retinopathy. It has also been shown to increase ocular blood flow and improve capillary perfusion (Gall and colleagues).
Radiation retinopathy is a predictable complication of radiotherapy. Careful monitoring is critical after radiotherapy to prevent irreversible loss of vision. A careful history of any form of radiation therapy is also important in aiding with the diagnosis.
Postradiation evaluation should include evaluation of tumor response, careful monitoring of the fellow eye and consideration of metastatic disease. Counseling patients of the potential ocular complications should be offered in all cases. Early diagnosis and prompt treatment are crucial to preventing deterioration of vision.
Boldt HC, et al. Ophthalmology. 2009;116:106-115.e1.
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Schmetterer L, et al. Am J Ophthalmol. 1996;121:169-176.
Stack R, et al. Clin Experiment Ophthalmol. 2005; 33:490-494.
Stallard H. Br J Ophthalmol. Monograph 6(suppl):1;1933.
Zamber RW, Kinyoun JL. Radiation Retinopathy. West J Med.1992;157:530-533.
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Edited by Leo P. Semes, OD, FAAO, a professor of optometry, University of Alabama at Birmingham and a member of the Primary Care Optometry News Editorial Board. He may be reached at 1716 University Blvd., Birmingham, AL 35294-0010; (205) 934-6773; email@example.com.