Palladium-103 plaque therapy for multifocal iris melanoma: Radiation of the entire anterior segment of the eye

An optimized 3T MRI scan protocol to assess iris melanoma with subsequent histopathological verification - A prospective study

INTRODUCTION

Magnetic resonance imaging (MRI) has demonstrated high levels of tissue contrast, accuracy and reproducibility in evaluating posterior uveal melanoma. Owing to smaller size, the role of MRI in detecting and characterising iris melanoma has not yet been explored.

AIMS

To develop a protocol to image iris melanoma and describe the MRI characteristics of histopathological-confirmed iris melanoma.

MATERIALS AND METHODS

An optimised MRI protocol, using a 3T MRI scanner and a 32-channel head coil, was developed to image iris tumours. A prospective, single-centre, 12-month study was conducted on all patients with lesions suspicious for iris melanoma. All patients were offered an MRI scan in addition to the standardised clinical procedures. Image quality comparison was made with existing clinical investigations. Iris melanoma characteristics on MRI are described.

RESULTS

A successful optimised MRI scan protocol was developed that was able to detect and characterise iris melanoma. One normal participant and five patients with subsequent histopathological-confirmed iris melanoma (n = 6) were recruited. Four patients completed the full MRI sequence. All iris melanoma were detected on at least one T1- or T2-weighted images. When compared to the vitreous, all iris melanomas demonstrated hyper-intensity on T1-weighted images and hypo-intensity on T2-weighted images. On T1-mapping, T1-values of iris melanoma demonstrated an inverse relationship with the degree of tumour pigmentation.

CONCLUSIONS

This study highlights an optimised, easily reproducible MRI scan protocol to image iris melanoma. Numerous MR imaging characteristics of iris melanoma are reported for the first time and a potential non-invasive tumour biomarker is described.

Ruthenium brachytherapy for iris melanoma

Purpose

The study aimed to review the long-term outcomes of ruthenium brachytherapy for iris and iridociliary melanoma.

Material And Methods

Medical records of patients who underwent ruthenium plaque treatment for iris and iridociliary melanoma at the Department of Ophthalmology, Poznań University of Medical Sciences, between 1999 and 2021 were retrospectively reviewed.

Results

We identified 24 patients, including 17 women and 7 men, with a median age of 61.5 years (range, 35-84 years). Median observation time before treatment was 3 months (range, 0-68 months). Nineteen (79%) patients received a treatment with 20 mm CCB plaque, 5 (21%) with 15 mm CCA plaque and 2 (8%) patients received total irradiation to the entire iridocorneal angle. Median follow-up was 67.5 months (range, 24-265 months). We noted one (4%) recurrence managed by irradiating the anterior segment. Twelve (50%) patients developed post-operative cataracts in a median time of 38 months following treatment, 5 (21%) required topical medications to control intraocular pressure, and one (4%) developed chronic macular edema (CME) that was managed with anti-VEGF therapy. Final visual acuity between 1.0 and 0.5 was observed for 16 (67%) patients, between 0.49-0.1 for 5 (21%) patients, and below 0.09 for 3 (12%) patients. Nine (37%) patients maintained final visual acuity stable; in 4 (17%) patients, it dropped more than 3 lines, and improved in 6 (25%) patients.

Conclusions

Ruthenium brachytherapy with standard applicators is an effective and safe way of treatment for iris and iridociliary melanoma. We observed no significant post-operative complications in a long-term observation.

First clinical implementation of Yttrium-90 Disc Brachytherapy after FDA clearance

PURPOSE

Herein, we study if high-dose-rate (HDR) yttrium-90 (⁹⁰Y) brachytherapy could be utilized by medical physicists, radiation oncologists, and ophthalmic surgeons.

METHODS AND MATERIALS

Yttrium-90 (⁹⁰Y) beta-emitting brachytherapy sources received United States Food and Drug Administration clearance for episcleral treatment of ocular tumors and benign growths. Dose calibration traceable to the National Institute of Standards and Technology as well as treatment planning and target delineation methods were established. Single-use systems included a ⁹⁰Y-disc affixed within specialized, multifunction, handheld applicator. Low-dose-rate to high-dose-rate prescription conversions and depth-dose determinations were performed. Radiation safety was evaluated based on live exposure rates during assembly and surgeries. Clinical data for radiation safety, treatment tolerability, and local control was collected.

RESULTS

Practice parameters for the medical physicist, radiation oncologist, and ophthalmic surgeon were defined. Device sterilizations, calibrations, assemblies, surgical methods, and disposals were reproducible and effective. Treated tumors included iris melanoma, iridociliary melanoma, choroidal melanoma, and a locally invasive squamous carcinoma. Mean calculated ⁹⁰Y disc activity was 14.33 mCi (range 8.8-16.6), prescription dose 27.8 Gy (range 22-30), delivered to depth of 2.3 mm (range 1.6-2.6), at treatment durations of 420 s (7.0 min, range 219 s-773 s). Both insertion and removal were performed during one surgical session. After surgery, each disc-applicator- system was contained for decay in storage. Treatments were well-tolerated.

CONCLUSIONS

HDR ⁹⁰Y episcleral brachytherapy devices were created, implementation methods developed, and treatments performed on 6 patients. Treatments were single-surgery, rapid, and well-tolerated with short-term follow up.

Locally Invasive Diffuse Iris Ring Melanoma Presenting as Unilateral Severe Glaucoma: Case Report and Review of Molecular Genetics

We report the clinical history and histopathological findings in a case of diffuse iris ring melanoma (DIM) and review the most recent literature and modern molecular genetics of this entity. An 85-year-old Hispanic man presented with severe unilateral glaucoma, managed at an outside institution for 2 years prior to presentation. Diffuse pigmentation was noted in the angle, on the intraocular lens implant, and in the vitreous without clear demonstration of a mass on ultrasound biomicroscopy. Workup for metastatic cutaneous melanoma was negative. Histopathological examination of the enucleated eye revealed a mixed cell type iris ring melanoma with diffuse intraocular involvement. Gene expression profiling (GEP) revealed a class 2 molecular signature indicating a very high risk for metastases. Unilateral glaucoma presenting with marked pigmentation in the anterior chamber angle should be managed as melanoma until proven otherwise. Iris ring melanomas are known to have an aggressive clinical course, and recent molecular analyses indicate that they are likely primarily GEP class 2 with a very poor prognosis, similar to the majority of ciliary body melanomas.

Current molecular and clinical insights into uveal melanoma (Review)

Uveal melanoma (UM) represents the most prominent primary eye cancer in adults. With an incidence of approximately 5 cases per million individuals annually in the United States, UM could be considered a relatively rare cancer. The 90-95% of UM cases arise from the choroid. Diagnosis is based mainly on a clinical examination and ancillary tests, with ocular ultrasonography being of greatest value. Differential diagnosis can prove challenging in the case of indeterminate choroidal lesions and, sometimes, monitoring for documented growth may be the proper approach. Fine needle aspiration biopsy tends to be performed with a prognostic purpose, often in combination with radiotherapy. Gene expression profiling has allowed for the grading of UMs into two classes, which feature different metastatic risks. Patients with UM require a specialized multidisciplinary management. Primary tumor treatment can be either enucleation or globe preserving. Usually, enucleation is reserved for larger tumors, while radiotherapy is preferred for small/medium melanomas. The prognosis is unfavorable due to the high mortality rate and high tendency to metastasize. Following the development of metastatic disease, the mortality rate increases to 80% within one year, due to both the absence of an effective treatment and the aggressiveness of the condition. Novel molecular studies have allowed for a better understanding of the genetic and epigenetic mechanisms involved in UM biological activity, which differs compared to skin melanomas. The most commonly mutated genes are GNAQ, GNA11 and BAP1. Research in this field could help to identify effective diagnostic and prognostic biomarkers, as well as novel therapeutic targets.

Plaque brachytherapy in iris and iridociliary melanoma: a systematic review of efficacy and complications

Purpose

To evaluate the efficacy and vision-threatening complication rate of plaque brachytherapy with iodine-125 (¹²⁵I), palladium-103 (¹⁰³Pd), and ruthenium-106 (¹⁰⁶Ru) for treatment of iris and iridociliary melanoma.

Material and methods

A literature review was done based on results yielded from searching PubMed, Embase, and Cochrane database, using following key words: iris melanoma, iridociliary melanoma, brachytherapy, iodine-125 brachytherapy, palladium-103 brachytherapy, and ruthenium-106 brachytherapy. Initially, relationships between mean radiation dose to apex and local recurrence and complication rate were analyzed, and then, a comparison was performed between ¹²⁵I, ¹⁰³Pd, and ¹⁰⁶Ru studies.

Results

Twelve retrospective and prospective studies were selected, with 491 patients treated primarily with plaque brachytherapy. The range of radiation dose to tumor apex were from 84 to 151.5 Gy. Ranges of mean and median of follow-up time were from 27 to 96 months. Local recurrence rate following brachytherapy ranged from 0 to 8%. A decrease in the average study dose was not associated with an increased local recurrence or metastasis rate (p = 0.373 and 0.195, respectively); however, an increase in radiation dose was associated with higher radiation-related cataract and glaucoma (p < 0.05). The rate of post-treatment glaucoma was higher in studies with ¹²⁵I plaque brachytherapy (p = 0.004).

Conclusions

For brachytherapy of iris and iridociliary melanoma, in a range of 84 to 150 Gy, an increase in radiation dose may increase the risk of complications, while the tumor control rate does not change.