Improved cosmesis in retinoblastoma patients treated with iodine-125 orbital irradiation.
Patients who are at risk for developing an orbital recurrence after enucleation of the eye for retinoblastoma are those with full thickness choroidal invasion or further extension into the sclera or extension into the optic nerve beyond the lamina cribrosa. The authors have treated these patients routinely with external irradiation to the orbit but this usually resulted in a dry contracted socket that often would not accept a prosthesis. An orbital implant was designed with 125I seeds in an attempt to improve the cosmetic result. It consisted of seven rows of 125I seeds, six of which were partially screened and implanted around the periphery of the orbit so that the contents were irradiated whilst reducing the dose to the bony orbit. The seventh central row was unscreened. A metal disc, with 125I seeds sealed to the posterior surface, was sutured beneath the eyelids thus protecting them and the accessory lacrimal glands. A TDF of 90-100 over two to three days was given. Thirteen patients have been treated, nine prophylactically and four therapeutically. Three of the latter patients have died of metastases but no local recurrences have been seen. All 13 patients were left with a moist socket that accepted a prosthesis.