Outcomes Following Treatment with Notched Proton Beams for Peripapillary Choroidal Melanomas

Area of Science:

• Ophthalmology
• Radiation Oncology
• Medical Physics

Background:

• Peripapillary choroidal melanoma poses treatment challenges due to proximity to vital visual structures.
• Standard radiotherapy often leads to vision loss; ocular proton therapy (OPT) uses shaped apertures.
• Aperture notching aims to minimize damage to the optic disc and fovea during OPT.

Purpose of the Study:

• To evaluate the efficacy of incorporating an aperture notch over the optic nerve during OPT for peripapillary choroidal melanoma.
• To determine if notched beams offer additional advantages in preserving vision compared to standard apertures.

Main Methods:

• Retrospective cohort study of 83 patients with peripapillary choroidal melanoma treated with OPT.
• Minimum follow-up of 2.5 years to assess visual acuity.
• Statistical analysis using a mixed effects model to compare vision loss and complications between notched and non-notched beams.

Main Results:

• A notched aperture for the optic disc is associated with an expected 0.058 logMAR of vision saved at 10 years post-OPT (p=0.077), considered clinically significant.
• The cohort treated with notched beams showed a slower rate of vision loss.
• No statistically significant advantage was found for notched beams in reducing enucleation or other complication rates.

Conclusions:

• Utilizing an aperture notch for the optic disc in OPT shows a trend towards long-term vision benefit for peripapillary choroidal melanoma.
• The findings suggest a clinically significant benefit in preserving vision with notched beams in this patient population.