Plaque Radiotherapy for Residual or Recurrent Iris Melanoma after Surgical Resection in 32 Cases

Abstract

To evaluate plaque radiotherapy for management of residual or recurrent iris melanoma after surgical resection. Retrospective, nonrandomized interventional case series. We included 32 patients with residual or recurrent iris melanoma after surgical resection. Custom designed iodine-125 plaque radiotherapy. Tumor control, recurrence, poor visual acuity, enucleation, metastasis, and radiation complications. There were 32 eyes with residual (n = 12) or recurrent (n = 20) iris melanoma after surgical resection that were treated with iodine-125 plaque radiotherapy. The residual melanoma was evident clinically in 3 cases and histopathologically in 9; plaque radiotherapy was delivered at a mean interval of 2 months after resection. For the recurrent cases, the mean interval from initial tumor resection to detection of recurrence was 58 months, at which time plaque radiotherapy was applied. For all cases, the mean tumor basal diameter was 6 mm (range, 1-13) and thickness was 2 mm (range, 0.8-4.0) at the time of radiotherapy. Anterior chamber seeding was present in 26 (81%) eyes and glaucoma in 11 (34%) eyes. Visual acuity at presentation was good (20/20-20/50) in 27 (84%), intermediate (20/60-20/150) in 3 (9%), and poor (≤20/200) in 2 eyes (6%). At 6 years after plaque radiotherapy, outcomes included complete tumor control in 87%, poor visual acuity in 9%, enucleation in 13% (for reasons of tumor recurrence [n = 3] and severe glaucoma [n = 1]), and metastasis in 3%. At 6 years, radiation complications included corneal epitheliopathy in 6%, scleral necrosis in 3%, cataract in 53%, elevated intraocular pressure (from tumor or radiotherapy) in 19%, and macular edema in 6%. Iodine-125 plaque radiotherapy is effective in the management of residual or recurrent iris melanoma after surgical resection, providing tumor control in 87% of patients at 6 years and avoiding enucleation in most cases.