Orbital and Periorbital Complications of Proton Beam Radiation Therapy for Intraocular Tumor

Abstract

To present our experience on the orbital and periorbital complications of proton beam radiation therapy (PBRT) in patients with intraocular tumor, apart from the treatment outcomes of disease control. Materials/Methods: We retrospectively reviewed the medical records of six intraocular tumor patients who had been treated with PBRT and referred to oculoplasty clinic of two medical centers from October 2007 to September 2014. Types of the adverse effects associated with PBRT, their managements, and progress were evaluated. In cases of anophthalmic patients who finally underwent enucleation after PBRT due to disease progression, orbital volume (OV) was assessed from magnetic resonance (MR) images with the "Pinnacle 3 program." Results: Among the 6 patients with PBRT history, 3 were uveal melanoma, and 3 children were retinoblastoma patients. Two eyes were treated with PBRT only, and the other 4 eyes ultimately underwent enucleation. Two eyes with PBRT only mainly suffered from radiation dermatitis and intractable epiphora due to canalicuitis or punctal obstruction. All four anophthalmic patients showed severe enophthalmic features with periorbital hollowness. OV analysis showed the difference between both orbits was less than 0.1cm 3 before enucleation, but increased to more than 2cm 3 after enucleation. Conclusion: PBRT for intraocular tumors could induce various orbital and periorbital complications. Especially when the enucleation is performed after PBRT due to disease progression, it should be kept in mind that significant enophthalmos and OV growth retardation can develop and can cause poor facial cosmesis as treatment sequelae.