Researchers at The New York Eye Cancer Center believe that eyes with highest risk for radiation maculopathy following plaque radiation therapy could benefit from early administration of monthly intravitreal anti-VEGF injections. They suspect that subclinical ischemic radiation vasculopathy begins immediately following plaque placement but only later becomes clinically apparent.

The pilot study retrospectively reviewed data for 14 patients diagnosed with choroidal melanoma treated with palladium-103 plaque radiotherapy. They were treated within six months of plaque placement—and every four to six weeks—with intravitreal injections prior to onset of radiation maculopathy. The researchers then case-matched them—by radiation dose to fovea, proximity to fovea and size of tumor—with 14 historical patients with choroidal melanoma treated with plaque radiotherapy, prior to the advent of anti-VEGF therapy.

The visual acuities between the two groups differed significantly at last follow-up. The anti-VEGF treated group showed an overall mean visual acuity of 20/32, compared with the case-matched group’s 20/160. When compared with their visual acuities measured at the time of diagnosis, nine (64.3%) in the anti-VEGF treated group showed improvement or no change in visual acuity, in contrast to only four (28.6%) in the case-matched group.

At their last follow-up exam, five (35.7%) of the injection-treated group were within two lines of their pre-treatment visual acuity compared with none of the case-matched cases. No patient in the anti-VEGF group lost less than three lines of vision, compared with 10 patients in the case-matched group. The researchers note that visual acuity improvements were primarily due to resolution of the adjacent retinal detachment and intra-retinal fluid associated with the subfoveal tumor.

The study concludes that its findings support the need for a prospective randomized clinical trial or retrospective multicenter registry to validate the use of intravitreal anti-VEGF injections to potentially prevent or delay radiation maculopathy-related vision loss.

Powell BE, Finger PT. Immediate post-plaque anti-VEGF therapy prevents or delays radiation maculopathy. Ophthalmol Retina. January 22, 2020. [Epub ahead of print].