Survival and Ocular Outcomes in Iris and Iridociliary Melanoma Patients aftert Proton Beam Irradiation

Purpose: We evaluated ocular outcomes and survival in patients with iris or iridociliary melanomas treated with proton irradiation. Most uveal melanomas arise in the choroid but a small number arise in the iris and/or ciliary body.  Tumor excision or irradiation can be used to treat these melanomas. 

Methods:This retrospective chart review included patients diagnosed with iris or iridociliary melanomas who were treated with proton irradiation between 1993 and 2013 at MEEI (n=41).  Mean follow-up for patients alive at the end of the observation period was 6.7 years (range: 10.6 months - 20.2 years). Loss of visual acuity and development of radiation-induced complications were evaluated in all patients. Melanoma-specific mortality rates were calculated and compared in patients with iris only tumors and iridociliary tumors.

Results:Of patients with a baseline visual acuity of better than 20/200 (Snellen equivalent), 44% (n=16) experienced loss of acuity to worse than 20/200 while under observation. Common complications included cataract formation (41.5% of patients) and increased intraocular pressure (> 25 mmHg) 58.8%). Seven of 31 patients (22.6%) with iridociliary melanomas died due to uveal metastasis, while no patients with iris melanoma died due to melanoma.

Conclusions: Proton irradiation is an excellent treatment option for patients with iris and iridociliary melanoma.  No surgery is required compared to other methods of treatment and complications are similar to those seen after plaque radiotherapy.