OC-0246: Visual outcomes of parapapillary uveal melanomas following proton beam therapy

Purpose: In parapapillary melanoma patients, radiation-induced optic complications are frequent and visual acuity is often compromised. We investigated dose-effect relationships for the optic nerve with respect to visual acuity after proton therapy.Methods and Materials: Of 5205 patients treated between 1991 and 2014, those treated using computed tomography (CT)-based planning to 52 Gy (prescribed dose, not accounting for relative biologic effectiveness correction of 1.1) in 4 fractions, with minimal 6-month follow-up and documented initial and last visual acuity, were included. Deterioration of >= 0.3 logMAR between initial and last visual acuity results was reported.Results: A total of 865 consecutive patients were included. Median follow-up was 69 months, mean age was 61.7 years, tumor abutted the papilla in 35.1% of patients, and tumor-to-fovea distance was <= 3 mm in 74.2% of patients. Five-year relapse-free survival rate was 92.7%. Visual acuity was >= 20/200 in 72.6% of patients initially and 47.2% at last follow-up. A wedge filter was used in 47.8% of the patients, with a positive impact on vision and no impact on relapse. Glaucoma, radiation-induced optic neuropathy, maculopathy were reported in 17.9%, 47.5%, and 33.6% of patients, respectively. On multivariate analysis, age, diabetes, thickness, initial visual acuity and percentage of macula receiving 26 Gy were predictive of visual acuity. Furthermore, patients irradiated to >= 80% of their papilla had better visual acuity when limiting the 50% (30-Gy) and 20% (12-Gy) isodoses to <= 2 mm and 6 mm of optic nerve length, respectively.Conclusions: A personalized proton therapy plan with optic nerve and macular sparing can be used efficiently with good oncological and functional results in parapapillary melanoma patients. (C) 2016 Elsevier Inc. All rights reserved.