Iodine‐125 orbital irradiation : improvement of cosmetic results for patients needing postenucleation irradiation

Abstract

Abstract Purpose Patients enucleated for malignant intraocular tumors (as retinoblastoma or uveal melanoma) that have extrascleral extension and/or optic nerve resection margin involvement, are at risk of orbital recurrence. These enucleated orbits were previously treated with external beam radiotherapy which induced late sequelae, in particular facial atrophy. Iodine 125 Orbital brachytherapy (BRT) was first realised in 1983 in South Africa as a technique to irradiate the content of the orbit while minimizing the dose to the surrounding bone and eyelids. We report our experience since 2000 with this technique Methods Six nylon tubes containing 125 I seeds were implanted though the eyelids around the periphery of the orbit. Each contained a metal gutter that screened the outer part of the seeds from the bony orbit. A seventh unscreened tube was placed in the center and a golden plaque with 125 I seeds on its inner surface was secured beneath the eyelid. The reference dose around the target was 45 Gy for retinoblastoma and 60 Gy for uveal melanoma Results Since 2000 13 patients underwent BRT : 9 retinoblastomas (median follow up 36 months, 1 child died of craniospinal metastasis), 3 uveal melanomas (median follow up 55 months, 1 patient developed a metastatic disease), and 1 medulloepithelioma (median follow up 45 months). No patient developed orbital recurrence after BRT. Regarding cosmesis, results were much more acceptable than with other forms of irradiation with a normal size prothesis adaptation Conclusion 125 I orbital brachytherapy is an effective method of irradiating the orbit to prevent recurrent tumor after enucleation with better cosmesis results than with other forms of irradiation, especially in case of children Commercial interest