Stereotactic radiotherapy for uveal melanoma: A case report

Abstract

Uveal melanoma (UM) is the most common primary intraocular malignancy worldwide. Surgical intervention and radiation therapy (RT) are the primary treatment options. Given the complexity and cosmetic discomfort associated with eye enucleation, this method is less frequently used. As a result, RT, including photon therapy, proton therapy and brachytherapy, has become the treatment of choice. Traditionally, plaque brachytherapy has been the most commonly used in clinical practice. However, the question of which type of radiation therapy is the most effective, safe, commonly available and cost-effective remains open. The present study provided a follow-up analysis of a patient with UM who was treated using the image-guided volumetric modulated arc therapy (IG-VMAT) technique. A complete response without complications and symptom relief were noted one and a half years after treatment. The present findings suggest that photon external beam radiotherapy using the IG-VMAT technique may offer a viable and safe alternative for the management of UM. This approach potentially sidesteps the complex and morbid aspects of surgical intervention and plaque brachytherapy. Owing to the limited sample size, a more robust understanding of the efficacy and safety of this treatment will require the analysis of additional cases. Further research with a larger cohort is essential to validate these preliminary observations.

Keywords: radiotherapy; stereotactic body radiation therapy; uveal melanoma.

Figure 1

(A) Ophthalmoscopy (May 2016). The black arrows indicate a hyperpigmentation lesion with sharp edges measuring 7x9 mm nasally from the optic disc in the left eye. (B) Ocular fundus in the infrared spectrum.

Figure 2

Orbit MRI with i/v contrast from October 2021. (A) T1-weighted image and (B) T2-weighted image. The red arrows indicate homogeneous contrast uptake in the posterior part of the left eyeball, adjacent with a wide base to the membranes of the eye, measuring 12x7x9 mm. (С) Initial ¹⁸F-fluorodeoxyglucose positron emission tomography/CT. The red arrow indicates a low accumulation of radiopharmaceuticals (maximum standardized uptake volume, 2.52).

Figure 3

Mapping of the treated lesion of the patient, based on the pre-irradiation therapy brain CT scan fused with the brain MRI in three projections: (A) Axial plane, (B) sagittal plane, (C) frontal plane during the treatment planning. (D) Dose distribution for stereotactic body radiation therapy using the image-guided volumetric modulated arc therapy method. The color wash represents the dose in Gy.

Figure 4

Dose volume histogram. PTV, planning target volume; Lt, left; GTV, gross tumor target volume.

Figure 5

(A) Initial orbit MRI with i/v contrast. The red arrow indicates the tumor before treatment. (B) Orbit MRI with i/v contrast. The red arrow indicates the decrease in tumor size in the left eye six months after radiation therapy. (C) Final orbit MRI with i/v contrast a year after radiation therapy. The red arrow indicates complete response in the left eye.