Diffuse choroidal hemangioma: IMRT versus episcleral plaque brachytherapy

The purpose of this review is to demonstrate the safety and procedures involved in the use of intensity-modulated radiation therapy (IMRT) and three-dimensional (3D)-conformal techniques for the management of diffuse choroidal hemangioma (DCH) and to compare dosimetric outcomes of these techniques to simulated episcleral plaque brachytherapy in the same cohort of 10 patients (11 eyes) with DCH.

A single institutional retrospective review of patients with Sturge-Weber syndrome associated DCH managed with IMRT (20 Gy in 10 fractions). Those same patients were planned for simulated brachytherapy and simulated doses to the fovea, disc, and lens were collected. The dose to organs at risk (critical visual and surrounding structures) was compared to determine potential long-term risks.

Ten patients (11 eyes) examined in this review were treated between 2005 and 2023. The use of IMRT and 3D allowed for effective coverage of the planning target volume (PTV) with low doses to critical visual and surrounding structures. Doses to the fovea, disc, and lens using external beam radiotherapy (EBRT) were uniform ranging from 1784 to 2151 cGy, 1695-2204 cGy, and 260-1579 cGy, respectively. Doses to the fovea, disc, and lens using episcleral plaque brachytherapy had ranged from 270 to 12270 cGy, 20623829 cGy, and 270-618 cGy, respectively.

IMRT and 3D-conformal technique used to deliver 20 Gy in 10 fractions provides a uniform safe plan in patients with DCHs with reasonable sparing of the lens, fovea, and optic disc. Simulated brachytherapy yielded variable radiation exposure to critical visual and surrounding structures with potential risk of vision-threatening toxicity. Use of EBRT or brachytherapy should be considered on a case-by-case basis driven by estimated radiation dosimetric parameters.