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

Objective: 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.

Methods: 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.

Results: 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 ≥20/200 (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).

Conclusions: 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.