Graves' ophthalmopathy treated with protracted hypofractionated low-dose adaptive radiotherapy: case report and review of the literature.

Graves' ophthalmopathy (GO) is the most common extra-thyroidal manifestation of Graves' disease. The treatment options for GO are high-dose glucocorticoids, selenium, rituximab, cyclosporine, orbital radiotherapy (RT), and surgery. A 43-year-old male patient was referred to our clinic with complaints of severe bilateral proptosis, diplopia, and orbital pain at both globes for 1 year. Pretreatment magnetic resonance imaging revealed bilateral proptosis, the expansion of bilateral optic nerves sheath, the increase of right medial muscle thickness, and a mass at the right eyehole. Patient was treated with 1 Gy per fraction per week with a total dose of 10 Gy over 10 weeks with adoptive intensity-modulated radiotherapy technique. During RT at 3rd and 6th weeks, a moderate shrinkage of the lesions was observed. The patient has been disease free, has had no complaints for 36 months, and has not required any surgical intervention. No late side effects such as retinopathy or cataract were observed. Orbital RT with innovative techniques may be considered as an initial local treatment for GO. With adoptive protracted low dose RT, a good clinical and radiological response could be seen without increasing early and late reactions.