Plaque radiotherapy of uveal melanoma with predominant ciliary body involvement

Background: There are several options for management of ciliary body melano ma, including plaque radiotherapy, charged particle irradiation, local rese ction, and enucleation. The choice of therapy depends on many factors, and plaque radiotherapy is often used. Objectives: To determine the outcome of plaque radiotherapy in the manageme nt of ciliary body melanoma and to identify the risk factors associated wit h the development of radiation complications, tumor recurrence, metastasis, and melanoma-related death after plaque radiotherapy of ciliary body melan oma. Methods: We analyzed the clinical records of 136 patients with ciliary body melanoma who were treated with plaque radiotherapy between July 1976 and J une 1992. Results: The median follow-up period was 70 months. Using Kaplan-Meier surv ival estimates, the most frequent radiation complication at 5 years' follow -up was cataract, developing in 38% of the patients, followed by neovascula r glaucoma (21%), retinopathy (20%), scleral necrosis (12%), and vitreous h emorrhage (11%). Visual acuity decrease (by greater than or equal to 3 Snel len lines) was noted in 40% of the patients at 5 years. Kaplan-Meier estima tes showed that 8% of the patients developed recurrence, 28% had metastasis , and 22% died of melanoma-related causes by 5 years. Univariate analysis d emonstrated that the factors predictive of radiation cataract were superona sal (P = .003) and inferior tumor meridian (P = .02) compared with inferona sal meridian and apex dose rate greater than 57 cGy/h (P = .05). The develo pment of neovascular glaucoma was significantly related to iris involvement with the ciliary body tumor (P<.001). The factors predictive of developmen t of radiation retinopathy were base dose rate greater than 230 cGy/h (P = .03) and the presence of diabetes mellitus (P = .05). The only predictor of metastasis was tumor thickness greater than 7 mm (P = .02). The risk facto rs for melanoma-related death were the presence of metastasis (P<.001), tum or thickness greater than 7 mm (P = .02), and recurrence (P = .02). Multiva riate analyses showed that the most significant variables predictive of the development of scleral necrosis were intraocular pressure greater than 15 mm Hg (P<.001) and tumor thickness greater than 7 mm (P = .007). The most s ignifi cant predictive factors for vitreous hemorrhage were visual acuity o f 20/40 to 20/200 (P = .02) and intraocular pressure greater than 15 mm Hg (P = .02). The best subset of independent predictors of vision decrease wer e mushroom tumor shape (P = .002), age older than 61 years (P = .006), and superonasal meridian (P = .04). The risks for melanoma-related death were p resence of metastasis (P<.001) and tumor thickness greater than 7 mm (P = . 01). There was no group of significant variables predictive for radiation c ataract, neovascular glaucoma, retinopathy, tumor recurrence, and metastasi s in multivariate analysis. Conclusions: Plaque radiotherapy offers 92% 5-year local control rate for c iliary body melanoma. Metastasis occurs in 28% of the patients treated with this method by 5 years. Patients with tumors greater than 7 mm in thicknes s are at greater risk than patients with thinner tumors for metastatic dise ase and melanoma-related death. Major radiation complications include radia tion cataract, neovascular glaucoma, retinopathy, and scleral necrosis.