Outcomes After Proton Beam Therapy for Large Choroidal Melanomas in 492 Patients

Abstract

To evaluate proton beam therapy (PBT) as a means to preserve the eye and spare some vision while not deteriorating survival in patients with large choroidal melanomas. This is a retrospective, consecutive cohort study of patients with T3-4 choroidal melanomas according to the 7th edition of the American Joint Cancer Classification treated with PBT over a 24-year period. A total of 492 patients were included. Mean (range) tumor thickness and diameter were 8.77 (2-15) mm and 14.91 (7-24.1) mm, respectively. Mean macular and optic disc distance were 4.56 (0-19.9) mm and 4.59 (0-22.1) mm, respectively. Mean follow-up was 61.9months. Rates of neovascular glaucoma (NVG) and enucleation (mainly for local recurrence or NVG) were 27.0% and 19.5%, respectively. Enucleation rates decreased over time. The 5-year local control was 94%. Mean baseline visual acuity was 20/63, and visual acuity ≥20/200 was preserved in 20% of patients. At 5 years, 25% of T3 patients presented with metastasis; overall and specific survival rates were 65% and 75%, respectively. Local control after PBT remained good with increasingly manageable complications and fewer secondary enucleations over time for these large melanomas. As PBT does not seem to deteriorate survival in these patients having a high risk of metastasis, PBT may be considered as a safe and efficient alternative to enucleation in patients with large choroidal melanoma, and may help tospare some vision.