Radiation optic neuropathy and retinopathy in patients with presumed benign intraorbital tumours treated with fractionated stereotactic radiotherapy

Abstract

Purpose: To assess the long-term effects of fractionated stereotactic radiotherapy (fSRT) for the treatment of (presumed) benign intraorbital tumours on visual acuity, visual fields, globe and eyelid position, and complications including radiation retinopathy and deviations of retinal nerve fibre layer (RNFL) on OCT. Methods: Multi-centre retrospective follow-up study of a consecutive series of 25 patients treated in the Rotterdam Orbital Center (collaboration between Erasmus Medical Center and Rotterdam Eye Hospital) between 2002 and 2018. Data on the dose of fSRT, visual acuity, Humphrey field analyser (HFA) perimetry, globe and eyelid position were obtained from the medical records. Results: In this retrospective consecutive series of 25 patients with a median follow-up of 104 months (range 48–215 months), 80.0% of the patients had presumed optic nerve sheath meningioma and 20.0 % presumed cavernous haemangioma with signs suggestive of recent growth. In most patients, a better visual acuity and RNFL thickness were observed after stereotactic radiotherapy. Improvement of the visual field defects was observed after treatment, with a mean deviation of −14.98 dB (12.9 SD) before treatment versus −4.56 dB (10.8 SD) after treatment, respectively. Significant, but small changes in exophthalmometry values were observed with a mean of 14.92 mm (7.9 SD) versus 13.79 mm (7.3 SD) after treatment, respectively. Only 3 patients (15.0%) developed radiation retinopathy after stereotactic radiotherapy. All patients with radiation retinopathy had presumed optic nerve sheath meningioma. Conclusions: Based on our results, fSRT is an effective treatment modality for this subset of orbital tumours with few complications and good long-term visual and cosmetic outcomes. FSRT is non-invasive and safer than surgery for lesions in the posterior orbit or around the optic nerve.