Plaque radiation therapy for malignant melanoma of the iris and ciliary body

To report on plaque radiation therapy for malignant melanomas involving the iris and ciliary body.

Twenty-two eyes (22 patients) with anterior uveal melanomas were treated with (103)Pd ophthalmic plaque radiation therapy. Transillumination and ultrasonography were used to evaluate ciliary body involvement and posterior iris extension. Plaques were placed onto the cornea to treat the anterior tumor margins. The targeted-zone included the tumor and a 2 to 3 mm tumor-free margin. After plaque removal, patients were examined at 1 day, 7 days, 4 weeks, and then every 3 to 6 months thereafter. Systemic evaluations for possible metastatic disease were performed every 6 months.

After plaque radiation therapy, the melanomas decreased in thickness (mean 47%) in all 22 eyes, and no secondary enucleation was performed. One patient died of metastatic melanoma 5 years after radiation therapy. Despite anterior plaque placement that covered portions of the cornea, no epiphora, eyelash loss, or visually significant corneal opacities were noted. Whereas 15 of 21 phakic eyes (71%) developed secondary cataract, no eyes developed ischemic or neovascular radiation maculopathy. Four eyes were noted to have glaucoma before treatment, and two developed it after irradiation. Twenty of 22 eyes (91%) were within 2 lines of their pretreatment visual acuity. After radiation, the mean +/- SD follow-up was 56 +/- 34.4 months (range, 9 to 117 months).

Plaque radiotherapy of melanomas involving the iris and ciliary body resulted in excellent local control with preservation of vision. Although there was high incidence of secondary cataracts, (103)Pd plaque radiation therapy resulted in no visually significant corneal opacity or radiation retinopathy.