Yttrium-90 Episcleral Plaque Brachytherapy for Choroidal Melanoma

Abstract

Purpose: To describe the first use of high-dose-rate yttrium-90 disc brachytherapy for choroidal melanoma. Methods: A 72-year-old patient had a cT1-category choroidal melanoma characterized by the presence of orange pigment, increasing subretinal fluid (SRF), and enlarging tumor thickness. It was treated with single-session, light-guided, light-defined yttrium-90-disc brachytherapy. Results: A specialized handheld applicator provided with 4 encircling lights was used to guide plaque placement and localize treatment. Unlike low-dose-rate plaques, high-dose-rate yttrium-90 required only 3 minutes 39 seconds. In this case, treatment did not require episcleral sutures, muscle relocation, outpatient dwell time, or a second surgery. High-dose-rate treatment improved radiation safety by eliminating perioperative exposure to health care personnel, the community, and the family. At the 13-month follow-up, the SRF and tumor thickness were diminished. There was no secondary cataract, radiation retinopathy, maculopathy, or optic neuropathy, and the visual acuity was 20/20. Conclusions: Yttrium-90 brachytherapy allowed for single-surgery, minimally invasive, outpatient irradiation of a choroidal melanoma.

Keywords: brachytherapy; choroid; high-dose rate; melanoma; plaque; yttrium-90.

Figure 1.

Radiation fields anterior, posterior, and lateral to the yttrium-90 disc are shown. The inset values were calculated from Rivard et al. (Illustration by Toby S. Welles.)

Figure 2.

(Top left) Fundus photograph (before yttrium-90 high-dose-rate brachytherapy) shows a small inferior choroidal melanoma with orange pigment lipofuscin (arrow). (Top middle) A 3-dimensional optical coherence tomography cross-section of the tumor shows subretinal fluid (SRF) over its apex. (Top right) A midphase fluorescein angiogram shows focal hyperfluorescence corresponding to the previously noted SRF. (Bottom) Early resolution of the orange pigment (left), SRF (middle), and minimally decreased fluorescein hyperfluorescence 13 months after yttrium-90 high-dose-rate brachytherapy.

Figure 3.

(Top) Lighted nodes on the anterior surface of the iWand P. (Bottom) Lighted nodes in place around the choroidal melanoma. Placement position of the yttrium-90 disc was ensured. (Illustration by Toby S. Welles.)

Figure 4.

High-dose-rate vs low-dose rate brachytherapy for choroidal melanoma. Abbreviations: ¹⁰³Pd, palladium-103; ¹⁰⁶Ru, ruthenium-106; ¹²⁵I, iodine-125; ⁹⁰Sr, strontium-90; ⁹⁰Y, yttrium-90. Community, outpatient community radiation exposure; Distance rule, the distance a patient is required to stay away from others as an outpatient; Distancing rule, >3 feet away from others required in New York State for ¹²⁵I and ¹⁰³Pd, in-patient hospitalization for ¹⁰⁶Ru; HDR, high-dose rate; LDR, low-dose rate.