Ophthalmic applicator displacement as a method of treating large diffuse uveal melanomas

Abstract

Purpose: The presentation of results of an ophthalmic plaque displacement as a brachytherapy treatment method of large diffuse uveal melanomas.

Material and methods: This was a retrospective analysis of treatment results of 9 patients with large diffuse uveal melanomas using ophthalmic plaque displacement. Patients were treated with this method in our center between 2012 and 2021 (last follow-up visit in 2023). To achieve appropriate radiation dose distribution for large tumors with a base greater than 18 mm, brachytherapy (¹⁰⁶Ru in 7 patients and ¹²⁵I in 2 patients) with applicator displacement was used as primary treatment. Median follow-up was 2.9 years, and for patients with positive primary treatment results, it was 1.7 months. Median time to local relapse was 2.3 years.

Results: In 5 patients, a positive result of local treatment was obtained, out of whom, one patient underwent enucleation due to complications. In the next 4 cases, local recurrence developed. In all tumors, the use of applicator displacement method caused that planning target volume (PTV) was effectively covered with treatment isodose.

Conclusions: Brachytherapy with ocular applicator displacement allows for the treatment of tumors with base measurements larger than 18 mm. The application of this method may be considered as an alternative for eye enucleation in particular cases of large diffuse tumors, such as a neoplasm of the eye with vison, or when a patient does not consent to enucleation.

Keywords: applicator displacement; brachytherapy; diffuse uveal melanoma; enucleation; ocular melanoma; ophthalmic applicator; plaque displacement; uveal melanoma.

Fig. 1

Ultrasound images of the melanoma before (A), two (B), and four (C) years after the treatment, showing a part of the tumor located in the posterior pole and in the area of the equator

Fig. 2

Picture of the eye fundus before (A) and four years after treatment (B) of large uveal melanoma using applicator displacement

Fig. 3

Treatment plan: ¹⁰⁶Ru exposition pattern in 3D orbit model

Fig. 4

Treatment plan: the scope of covering the tumor with isodoses after ¹⁰⁶Ru applicator displacement