Complications after proton beam therapy for uveal malignant melanoma. A clinical and histopathologic study of five cases.

Proton beam therapy for uveal malignant melanoma has been advocated as effective therapy because of documented reduction in tumor size and few clinical complications. However, some eyes have been removed because of adverse effects. The authors report the clinical courses and pathologic findings of five eyes enucleated after proton beam irradiation. Neovascular glaucoma had developed in three eyes, two eyes had vitreous hemorrhage, and two had extraocular extension. The tumors in the radiation treatment field showed continued postirradiation growth clinically in four of the five eyes, and mitotic activity histologically in all five cases. Two and one half years after irradiation, and nearly 2 years after subsequent enucleation, one of those two patients had biopsy-proven liver metastases, and later died. Despite the considerable success rate of proton beam irradiation, the potential for clinical complications and subsequent tumor growth remains.