23-mm iodine-125 plaque for uveal melanoma: benefit of vitrectomy and silicone oil on visual acuity

To review outcomes in mostly large uveal melanoma treated with a 23-mm-diameter iodine-125 plaque, the largest size available at our center, and the influence of vitrectomy and silicone oil 1000 centistokes for radiation attenuation. A one-to-one matched case-control comparison was performed. Case patients were treated with a 23-mm-diameter iodine-125 plaque and vitrectomy with silicone oil 1000-cSt placement. Control cases, treated with 23-mm plaque alone, were matched to cases with respect to tumor size and distance from tumor apex to optic nerve and fovea. Postoperative complications, visual acuity and metastasis were reviewed. Twenty case patients with uveal melanoma treated with a 23-mm plaque were identified. The final logMAR vision was 0.83 in case patients and 2.06 in control patients (P = 0.0064); the change from pre-treatment to last follow-up logMAR vision was 0.70 in cases and 1.62 in controls (P = 0.019). Of good vision outcomes, 65 % of cases and 25 % of controls achieved vision aeyen20/200 (P = 0.025). Of poor vision outcomes, 35 % of cases and 80 % of controls achieved vision < 20/200 (P = 0.0053), and 5 % of cases and 35 % of controls achieved light perception or no light perception vision (P = 0.044). Thirty-nine of the 40 eyes (98 %) achieved local tumor control. Metastasis occurred in 15 % of cases and 45 % of controls (P = 0.082). Iodine-125 brachytherapy for mostly large uveal melanoma is effective in achieving local tumor control. Furthermore, combining brachytherapy with vitrectomy and silicone oil 1000-cSt for radiation attenuation significantly improves vision over the use of plaque alone.