PHOTODYNAMIC THERAPY OF PIGMENTED CHOROIDAL MELANOMAS OF GREATER-THAN3-MM THICKNESS

Purpose: The purpose of the study is to determine the effect of photod ynamic therapy in the destruction of experimental pigmented choroidal melanomas greater than or equal to 3 mm in thickness using a liposomal preparation of benzoporphyrin derivative, verteporfin. Methods: Pigme nted choroidal turners were established in 32 New Zealand albino rabbi t eyes, Animals were treated with daily injections of cyclosporine, an d tumor growth was followed by serial fundus examinations and ultrason ography. When a tumor exceeded 3 mm in thickness (tumor height ranged from 3.1-4.6 mm), the authors administered benzoporphyrin derivative i ntravenously (1 mg/kg) and irradiated the tumor at 692-nm through an a rgon-pumped dye laser at different total light doses ranging from 60 t o 120 J/cm(2), Control animals were treated with light or benzoporphyr in derivative only. Each animal then was followed-up for 4 to 6 weeks by fundus photography, fluorescein angiography, and ultrasonography. R esults: All animals treated with benzoporphyrin derivative and light a t fluences of greater than or equal to 80 J/cm(2) showed complete tumo r arrest, In contrast,both control groups showed continuous tumor grow th in all animals with tumors filling most of the vitreous cavity by 3 weeks. Histologic examination results of tumors treated with dye plus light immediately after treatment showed prominent vascular closure, No vascular changes were noted in the control eye treated with light o r dye alone. Examination results of the eyes that showed tumor regress ion after a 4-week follow-up period showed tumor necrosis and extensiv e infiltration of mononuclear cells and pigment-laden macrophages at t he tumor site, Conclusion: These data suggest that photodynamic therap y may have a role in the management of pigmented choroidal melanomas.