EPISCLERAL PLAQUE RADIOTHERAPY IN THE TREATMENT OF UVEAL MELANOMAS

During an 8-year period, 85 patients with uveal melanomas were treated with episcleral plaque radiotherapy (EPRT). The T-stage was: T1 - 3 (4%), T2 - 29 (34%) and T3 - 53 (62%). The mean tumor elevation was 6.1 mm. Radiation dose was prescribed at the tumor apex and at D5 mm. The mean D5 mm dose was 150.1 Gy (range 70.5-430 Gy) and the mean dose at the apex was 102.6 Gy (range 29.8-200 Gy). Useful vision (> 5/200) was maintained in 73% of patients. The 5-year actuarial survival was 88%. Metastatic disease developed in 9 (11%) patients, 6 of whom died of their disease. Basal tumor dimensions were important factors predicting metastatic disease, p = 0.002. A decrease in tumor elevation was seen in 82%. There was a much lower incidence of decrease in tumor radial and circumferential dimensions, 47.5 and 46%, respectively, p < 0.001. Treatment complications were common (56%), particularly in patients with large tumors (72%), p = 0.04. The incidence of complications was higher in patients treated prior to 1988 as compared to those who were treated more recently (67 vs 35%, p = 0.010). There were 13 (15%) patients who had enucleation. This included 12 treated before 1986 and 1 patient treated subsequently (46 vs 2%, p < 0.001). In a univariate analysis, tumor height and radiation dose at D5 mm were important factors predicting enucleation, p = 0.004. In a multivariate analysis, however, the most important factor predicting enucleation was treatment administration prior to 1986, p < 0.001). A sharp decrease in the incidence of severe complications, including enucleation, as seen after 1985, is likely due to a major effort in treatment optimization.