Post-brachytherapy tumor endoresection for treatment of toxic maculopathy in choroidal melanoma

Description and Characteristics of Ocular Tumor Lysis Syndrome

Introduction

The aim of the study was to describe and evaluate characteristics of ocular tumor lysis syndrome (OTLS) in eyes with uveal melanoma.

Methods

Retrospective chart review of all patients with OTLS at the University of Colorado from 2009 to 2021. Data collected included patient demographics, tumor characteristics, radiation dosimetry, gene expression profiling (GEP), OTLS characteristics, management, and outcomes.

Results

Seven eyes of seven patients with uveal melanoma treated with I-125 brachytherapy developed OTLS. Average age was 59 years (range 32-83). Mean apical height was 8.6 mm (range 6-11); mean diameter was 12.7 mm (range 8.5-15.3). All tumors were treated with plaques ≥16 mm in diameter. On presentation, 5/7 tumors had subretinal fluid, and 6/7 had collar-button configuration. OTLS presented as extensive pigment dispersion in the vitreous in all eyes, subretinal pigment and/or retinal detachment in 4/7 eyes, vitreous hemorrhage in 2/7 eyes, and anterior chamber pigment in 3/7 eyes. Four tumors were GEP class 1, two were class 2, and one was unclassified. Biopsy route was trans-scleral in 4/7 eyes and trans-vitreal in 3/7 eyes. OTLS occurred 2-4 weeks after an intraocular procedure in 5/7 eyes. All underwent pars plana vitrectomy. Cytology of the vitreous, obtained in five cases, showed pigment laden macrophages and hemorrhage, but only 1/5 eyes had viable malignant cells. Four eyes were stable at the last follow-up, two were enucleated, and one had no light perception from pigmentary glaucoma. Poor vision (<20/200) occurred in 6/7 cases. Three patients died from metastasis (tumors were GEP class 2, GEP class without subclassification, and no GEP classification performed).

Conclusions

OTLS is a rare but devastating complication of uveal melanoma. Common characteristics included large plaque diameter, presence of subretinal fluid, and collar-button shape. The extensively dispersed pigment is typically not malignant. Though poor vision is common, enucleation may be avoided in most eyes through vitreoretinal surgical repair.

Ocular Brachytherapy (Interventional Radiotherapy): Preserving the Vision

Uveal melanoma represents the most common intraocular neoplasia among adults. Brachytherapy (interventional radiotherapy; IRT) has a great advantage, when compared with enucleation, both in terms of organ and function sparing. The Collaborative Ocular Melanoma Study introduced into clinical practice a standardised procedure that allowed the equivalence of IRT with enucleation in terms of overall survival to be demonstrated. IRT is carried out by placing a plaque in direct contact with the sclera under the uveal melanoma. Several radioactive sources may be used, including 106-ruthenium, 125-iodine, 103-palladium and 90-strontium. It is a multidisciplinary procedure requiring the collaboration of interventional radiation oncologists and ophthalmologists in the operating theatre and medical physicists for an accurate treatment time calculation. It also relies on ultrasound imaging to identify the lesion and verifiy the correct plaque placement. An emerging tool of paramount importance could be the use of artificial intelligence and predictive models to identify those patients at higher risk of developing late side-effects and therefore who may deserve preventive and supportive therapies.

Surgical Approach in Intraocular Tumors

Surgery in intraocular tumors is done for excision/biopsy and the management of complications secondary to the treatment of these tumors. Excision/biopsy of intraocular tumors can be done via fine-needle aspiration biopsy (FNAB), transretinal biopsy (TRB), partial lamellar sclerouvectomy (PLSU), and endoresection. FNAB, TRB, and PLSU can be used in tumors that cannot be diagnosed by clinical examination and other ancillary testing methods. PLSU is employed in tumors involving the iridociliary region and choroid anterior to the equator. Excisional PLSU is performed for iridociliary and ciliary body tumors with less than 3 clock hours of iris and ciliary body involvement and choroidal tumors with a base diameter less than 15 mm. However, for biopsy, PLSU can be employed with any size tumor. Endoresection is a procedure whereby the intraocular tumor is excised using vitrectomy techniques. The rationale for performing endoresection is based on the fact that irradiated uveal melanomas may cause complications such as exudation, neovascular glaucoma, and intraocular pigment and tumor dissemination (toxic tumor syndrome), and removing the dead tumor tissue may contribute to better visual outcome. Endoresection is recommended 1-2 weeks after external radiotherapy. Pars plana vitrectomy is also used in the management of complications including vitreous hemorrhage, retinal detachment, and epiretinal membrane that can occur after treatment of posterior segment tumors using radiotherapy and transpupillary thermotherapy. It is important to make sure the intraocular tumor has been eradicated before embarking on such treatment.

New Perspectives for Eye-Sparing Treatment Strategies in Primary Uveal Melanoma

Simple Summary

Uveal melanoma is the most common intraocular cancer. The current eye-sparing treatment options include mostly plaque brachytherapy. However, the effectiveness of these methods is still unsatisfactory. In this article, we review several possible new treatment options. These methods may be based on the physical destruction of the cancerous cells by applying ultrasounds. Another approach may be based on improving the penetration of the anti-cancer agents. It seems that the most promising technologies from this group are based on enhancing drug delivery by applying electric current. Finally, new advanced nanoparticles are developed to combine diagnostic imaging and therapy (i.e., theranostics). However, these methods are mostly at an early stage of development. More advanced studies on experimental animals and clinical trials would be needed to introduce some of these techniques to routine clinical practice.

Abstract

Uveal melanoma is the most common intraocular malignancy and arises from melanocytes in the choroid, ciliary body, or iris. The current eye-sparing treatment options include surgical treatment, plaque brachytherapy, proton beam radiotherapy, stereotactic photon radiotherapy, or photodynamic therapy. However, the efficacy of these methods is still unsatisfactory. This article reviews several possible new treatment options and their potential advantages in treating localized uveal melanoma. These methods may be based on the physical destruction of the cancerous cells by applying ultrasounds. Two examples of such an approach are High-Intensity Focused Ultrasound (HIFU)—a promising technology of thermal destruction of solid tumors located deep under the skin and sonodynamic therapy (SDT) that induces reactive oxygen species. Another approach may be based on improving the penetration of anti-cancer agents into UM cells. The most promising technologies from this group are based on enhancing drug delivery by applying electric current. One such approach is called transcorneal iontophoresis and has already been shown to increase the local concentration of several different therapeutics. Another technique, electrically enhanced chemotherapy, may promote drug delivery from the intercellular space to cells. Finally, new advanced nanoparticles are developed to combine diagnostic imaging and therapy (i.e., theranostics). However, these methods are mostly at an early stage of development. More advanced and targeted preclinical studies and clinical trials would be needed to introduce some of these techniques to routine clinical practice.

Vitreoretinal Surgery in the Prevention and Treatment of Toxic Tumour Syndrome in Uveal Melanoma: A Systematic Review

Toxic tumour syndrome (TTS) is a particularly aggressive form of secondary vasculopathy occurring after radiation therapy of uveal melanoma due to the persistence of the necrotic tumour mass inside the eye. The development of TTS confers a particularly unfavourable functional and anatomical ocular prognosis, ultimately requiring enucleation in most cases if untreated. Vitreoretinal (VR) surgery has been successfully applied for treatment and prevention of TTS using both resecting and non-resecting techniques. In this systematic review, we aim to define characteristics of uveal melanomas benefiting the most from secondary VR surgery and to outline the optimal type and timing of VR intervention in such cases. Analysis of the literature reveals that endoresection should be performed within 3 months after radiotherapy to tumours thicker than 7 mm and with a largest basal diameter between 8 mm and 15 mm with post-equatorial location, especially after proton beam treatment. Alternatively, endodrainage remains a valid therapeutic option in eyes with macula-off retinal detachment, tumour diameter larger than 15 mm or ciliary body involvement. VR surgery can be successful in the management of TTS following radiotherapy for uveal melanoma when timing and indication are appropriately evaluated.

Treatment of radiation maculopathy and radiation-induced macular edema: A systematic review

Radiation maculopathy and radiation-induced macular edema are common, sight-threatening complications after radiotherapy, especially that used for uveal melanoma. While many treatment and preventive strategies have been proposed, management of these conditions is still challenging. Initially, treatments were based on the use of retinal laser, but the outcomes were poor. Subsequently, management has shifted toward injection of intravitreal antivascular endothelial growth factor or corticosteroids. We reviewed current clinical evidence, which mostly relies on small sample-sized and retrospective studies, for the management of radiation maculopathy and, in particular, radiation-induced macular edema. At present, the first-line approach is usually intravitreal antivascular endothelial growth factor. Intravitreal dexamethasone implantation may be an option for those with suboptimal response or contraindications to antivascular endothelial growth factor agents. Possible preventive treatments that require future study are intravitreal bevacizumab and ranibizumab, peripheral laser photocoagulation, and subtenon triamcinolone acetonide.

Complications and adverse events of plaque brachytherapy for ocular melanoma

Plaque brachytherapy is a well-accepted modality to manage selected cases of ocular melanoma. Although this modality provides validated oncologic and quality of life benefits, severe complications and adverse events can occur. This article reviews complications and adverse events of plaque brachytherapy, including scleral necrosis, strabismus, cataract, glaucoma, and retinopathies as well as management of these conditions. For practicing oncologists and ophthalmologists, these complications are important to understand, identify, and treat. Additionally, an understanding of common complications of brachytherapy should influence the decision of pursuing it as a treatment option.

Endoresection utilizing pars plana vitrectomy for benign and malignant intraocular tumors

PURPOSE OF REVIEW

Endoresection of intraocular tumors is a complicated procedure utilizing pars plana vitrectomy techniques. Though it has potential downsides and complications, there is potential for this technique in the treatment of malignant and benign intraocular tumors.

RECENT FINDINGS

Endoresection has been utilized in some form for the last three decades, but recent advances in vitreoretinal surgery have improved the technique. Endoresection is used most commonly to treat posterior uveal melanoma, but success in treating benign tumors, such as astrocytoma or retinal capillary hemangioblastoma has emboldened surgeons to expand its indications. It appears that removal of a malignant tumor, such as uveal melanoma may spare the eye some damaging effects of radiation retinopathy and radiation optic neuropathy. These benefits may occur even when the tumor is treated concurrently with plaque brachytherapy, proton beam irradiation, or stereotactic radiotherapy. The benefits of the technique are tempered, however, by the inherent difficulties associated with performing the surgery. These include potentially severe intraoperative bleeding, recurrent rhegmatogenous retinal detachment with proliferative vitreoretinopathy, air embolism, and recurrence of the tumor at the edge of the resection. Nonetheless, endoresection has recently been used for retinoblastoma in refractory cases in order to spare the globe.

SUMMARY

Endoresection is an advanced vitreoretinal surgical technique that has potential advantages in the treatment of malignant and benign intraocular tumors.

Plaque brachytherapy for posterior uveal melanoma in 2018: improved techniques and expanded indications

PURPOSE OF REVIEW

Plaque brachytherapy remains the dominant globe-sparing therapy of uveal melanoma. This report highlights recent advances, which have expanded plaque brachytherapy's uses as well as improved the surgical technique.

RECENT FINDINGS

Plaque brachytherapy is effective for tumors that may previously have demanded enucleation. Plaque brachytherapy can be used to control large melanomas as well as melanomas touching the optic nerve. Improvements in planning and design have made plaque therapy simpler for the surgical operator and may reduce collateral radiation damage to normal ocular structures. The COMS implies a required dose of 85 Gy to the tumor apex for treatment of uveal melanoma. However, multiple reports indicate that lower doses may be equally effective for tumor control while reducing radiation dose to uninvolved structures. Vitreoretinal surgeons can be called upon safely to treat long-term side effects of radiation or tumor death such as intractable vitreous hemorrhage or inflammation. Further, vitreoretinal surgeons have employed tumor endoresection as primary local tumor control or in combination with plaque brachytherapy.

SUMMARY

Plaque brachytherapy for uveal melanoma remains highly effective for local tumor control and prevention of metastasis. Indications for plaque brachytherapy have expanded, and the technique has improved.