HIGH-INTENSITY 125-IODINE (I-125) PLAQUE TREATMENT OF UVEAL MELANOMA

Purpose: Episcleral I-125 plaque therapy of uveal melanoma is an impor tant treatment modality to control tumor, salvage the globe, and poten tially preserve vision. We retrospectively analyzed our experience in 239 patients to assess treatment outcome with this technique. Methods and Materials: Between 1983 and 1990, 239 uveal melanoma patients were treated With I-125 plaques at the University of California, San Franc isco. High intensity I-125 seeds in the range of 3-20 mCi were used to give a minimum tumor dose of 70 Gy in 4 days. Initial mean tumor size was 10.9 mm x 9.2 mm x 5.5 mm with a range in tumor diameter from 4 t o 18 mm and tumor height from 1.9 to 11.1 mm. Best corrected pre-treat ment visual acuity was 20/200 or better in 92% of patients. Results: L ocal tumor control was maintained in 91.7% of patients with a mean fol low-up of 35.9 months; 19 patients had local tumor progression; mean t ime to progression was 27.3 mo (1.8 to 60.1 mo). Actuarial local contr ol is 82% at 5 years. Multivariate analysis demonstrates significant c orrelation of local failure with larger maximum tumor diameter (p = 0. 0008), closer proximity to the fovea (p = 0.0001), lower radiation dos e (p = 0.0437), and smaller ultrasound height (p = 0.0034). The actuar ial incidence of distant metastases is 12% at 5 years with multivariat e analysis showing significant correlation only with maximum tumor dia meter (p = 0.0064). Visual outcome is 20/200 or better in 58% of patie nts. Conclusion: While the tumor control rates appear favorable, ocula r morbidity is significant. A current randomized trial comparing I-125 plaque with Helium ion therapy is in progress with specific compariso n of tumor control, survival, and visual outcome.