DEXAMETHASONE INTRAVITREAL IMPLANT VS RANIBIZUMAB IN THE TREATMENT OF MACULAR EDEMA SECONDARY TO BRACHYTHERAPY FOR CHOROIDAL MELANOMA

[Radiation-induced retinopathy: actual knowledge and new concepts]

Radiation retinopathy is an occlusive vascular pathology following radiotherapy, generally targeted on the eye or peri-ocular structures. Despite increasingly precise techniques (stereotactic radiosurgery, proton therapy, etc.), the inclusion of the retina in the radiation field is sometimes unavoidable. This can lead to a severe pathology, which can ultimately cause blindness or even the anatomical loss of the eye when neovascular glaucoma occurs, due to the abnormal proliferation of neovessels. Radiation retinopathy have been described for more than a century, but it has recently seen great advances in both diagnosis and treatment. The advances of efficient and less invasive examinations in our clinical practice, such as OCT-angiography, allows for easier screening and diagnosis at earlier stages. Thus a new approach to the pathology is necessary, first of all through new definitions and classifications including previously undetected minimal forms. Furthermore, the recent appearance of intravitreal therapies by injection of anti-VEGF or dexamethasone implants has drastically changed the visual prognosis of these patients, who were previously treated only by retinal photocoagulation of the ischaemic areas. Recent studies have even shown the effectiveness of these new molecules in preventing the development of radiation retinopathy. This review of the literature provides an update on this disease and details how these recent diagnostic and therapeutic developments may play a role in the management of this complication.

Non-Cancer Effects following Ionizing Irradiation Involving the Eye and Orbit

Simple Summary

The irradiation of tumors involving the eye or orbit represents a complex therapeutic challenge due to the proximity between the tumor and organs that are susceptible to radiation. The challenges include tumor control, as it is often a surrogate for survival; organ (usually the eyeball) preservation; and the minimization of damage of sensitive tissues surrounding the tumor in order to preserve vision. Anticipation of the spectrum and severity of radiation-induced complications is crucial to the decision of which technique to use for a given tumor. The aim of the present review is to report the non-cancer effects that may occur following ionizing irradiation involving the eye and orbit and their specific patterns of toxicity for a given radiotherapy modality. The pros and cons of conventional and advanced forms of radiation techniques and their clinical implementation are provided with a clinical perspective.

Abstract

The eye is an exemplarily challenging organ to treat when considering ocular tumors. It is at the crossroads of several major aims in oncology: tumor control, organ preservation, and functional outcomes including vision and quality of life. The proximity between the tumor and organs that are susceptible to radiation damage explain these challenges. Given a high enough dose of radiation, virtually any cancer will be destroyed with radiotherapy. Yet, the doses inevitably absorbed by normal tissues may lead to complications, the likelihood of which increases with the radiation dose and volume of normal tissues irradiated. Precision radiotherapy allows personalized decision-making algorithms based on patient and tumor characteristics by exploiting the full knowledge of the physics, radiobiology, and the modifications made to the radiotherapy equipment to adapt to the various ocular tumors. Anticipation of the spectrum and severity of radiation-induced complications is crucial to the decision of which technique to use for a given tumor. Radiation can damage the lacrimal gland, eyelashes/eyelids, cornea, lens, macula/retina, optic nerves and chiasma, each having specific dose–response characteristics. The present review is a report of non-cancer effects that may occur following ionizing irradiation involving the eye and orbit and their specific patterns of toxicity for a given radiotherapy modality.

Long-Term Outcomes in Uveal Melanoma After Ruthenium-106 Brachytherapy

Uveal melanoma is the most common primary intraocular malignancy. The aim of this retrospective study was to report the results after ruthenium-106 (Ru-106) plaque brachytherapy for uveal melanoma in terms of tumor control, visual acuity, radiation-related complications, tumor recurrence, metastases, and patients’ survival rate during 4 years’ follow-up. A total of 355 eyes from 355 patients have been treated with Ru-106 plaque brachytherapy for uveal melanoma between February 2011 and March 2020. Five patients were lost to follow-up, and then 350 eyes of 350 patients (mean age 58 ± 11 years) were enrolled in this retrospective study. All patients underwent a complete ophthalmic examination including echography and spectral domain–optical coherence tomography. The mean follow-up was 4 years (3 months to 9 years). After treatment, the mean tumor thickness was reduced to 1.75 ± 0.21 mm. Radiation complications were found in 63% of patients: 38% showed radiation maculopathy, 11% had optic neuropathy, and 14% developed cataracts. Cancer-free survival was 99%, 97%, and 85%, respectively, at 5, 7, and 9 years. Ru-106 plaque brachytherapy represents a reliable treatment of uveal melanoma. This technique is valid and safe with a low rate of ocular complications during a long-term follow-up.

Radiation retinopathy intricacies and advances in management

Background: Radiation retinopathy is a chronic, progressive, vision-threatening complication from exposure to various radiation sources. While several treatment modalities are available, proper management for this disease is a continuing challenge with no consensus on the most efficacious.Objective: The aim of this article is to provide an updated review of the published literature on the course of the disease, available treatments and their efficacies, frequency of regimen, core issues in patient management, and additional newer treatment modalities, including possible prophylactic approaches.Value: We also highlighted the challenges encountered with managing chronically treated patients through an analysis of a clinical case report on a patient who was treated for several years with different modalities after a diagnosis of radiation retinopathy.

RETINAL MICROVASCULAR CHANGES IN UVEAL MELANOMA FOLLOWING CONBERCEPT INJECTION AFTER PLAQUE RADIOTHERAPY AS DETECTED BY OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

PURPOSE

To investigate macular microvascular characteristics imaged by optical coherence tomography angiography in patients with uveal melanoma following conbercept injections after plaque radiotherapy.

METHODS

Prospective comparative analysis comprising 15 patients with uveal melanoma with conbercept injections and 30 patients without conbercept injections after plaque radiotherapy by optical coherence tomography angiography. The conbercept group received intravitreal conbercept injections at the time of plaque removal, 1 month, 3 months, 6 months , 9 months and 12 months after plaque removal (total, 6 injections). The control group had no intravitreal conbercept injection.

RESULTS

After initiation of conbercept injections, superficial retinal vascular density in the whole image and parafoveal region were significantly higher at 6 months, whereas there was no significant difference at 9 months and 12 months. In analysis of variance analysis, superficial retinal vascular density in the whole image remained stable after conbercept injections (P = 0.069), whereas the superficial retinal vascular density decreased significantly after plaque radiotherapy in the control group (P = 0.011). In multivariable linear regression, a higher superficial retinal vascular density in the whole image region at 6 months was significantly associated with intravitreal conbercept injection (P = 0.018), wider tumor base (P = 0.026), and thinner tumor thickness (P = 0.04).

CONCLUSION

Optical coherence tomography angiography can provide a quantitative evaluation of early retinal microvascular changes after radiotherapy. Intravitreal conbercept treatment could partly relieve the retinal vascular damage in response to radiation therapy at early stage in patients with uveal melanoma; however, it may not be able to provide long-term positive functional outcomes.

Radiation Retinopathy: Detection and Management Strategies

A gradual shift in trend from primary enucleation to globe salvaging radiation therapy for the management of ocular tumors has resulted in the rise of several post-treatment ocular complications including radiation retinopathy. Radiation retinopathy is a chronic, progressive, and occlusive vasculopathy that can manifest anytime between 1 month to 15 years after starting radiation therapy. The aim of treatment in most of these cases is to prevent further vision loss. Treatment options such as laser photocoagulation, anti-vascular endothelial growth factor and intraviral steroids have been described. However, despite several advances in diagnostic and therapeutic modalities, a significant proportion of eyes with radiation retinopathy eventually go blind. This review summarises some of the clinical features, investigative modalities, and recent therapeutic strategies used in the management of radiation retinopathy.

Diagnostic methods and therapeutic options of uveal melanoma with emphasis on MR imaging-Part II: treatment indications and complications

Therapy of uveal melanoma aims to preserve the eye and its function and to avoid metastatic dissemination. The treatment choice is difficult and must keep into account several factors; the therapeutic strategy of uveal melanoma should therefore be personalized, sometimes requiring to combine different treatment techniques. Nowadays globe-sparing radiotherapy techniques are often preferred to enucleation. Plaque brachytherapy, the most commonly used eye-preserving therapy, is suitable for small- and medium-sized uveal melanomas. Proton beam radiotherapy is indicated for tumours with noticeable size, challenging shape and location, but is more expensive and less available than brachytherapy. Enucleation is currently restricted to advanced tumours, uveal melanomas with orbital or optic nerve involvement, blind and painful eyes because of treatment-related complications (neovascular glaucoma, chronic inflammatory processes). The effect of proton beam therapy on neoplastic tissue is related to direct cytotoxic action of the radiations, impairment of neoplastic vascular supply and immunologic response. Complications after radiotherapy are frequent and numerous and mainly related to tumour thickness, radiation dose and distance between the tumour and optic nerve. The purpose of this pictorial review is to provide the radiologists with awareness about diagnostic methods and therapeutic options of uveal melanoma. In the present second section, we discuss the therapeutic management of uveal melanoma, describing the main ocular-conserving radiotherapic techniques. We subsequently present an overview of the effects of radiations on neoplastic tissue. Lastly, we review ocular complications following radiotherapy that should be evaluated by radiologists during follow-up MRI examinations.

Iris Melanoma: Management and Prognosis

Iris melanomas represent 2–5% of uveal melanomas. Iris melanomas vary in their size, shape, degree of pigmentation and clinical behavior. The main local clinical complications of iris melanomas are tumor vascularization, ectropion uvea, pupillary distortion, pigment dispersion, sector cataract, chronic uveitis, hyphema and glaucoma with irreversible optic nerve damage. The most effective treatment for iris nevus and melanoma remains debatable; treatment modalities have been proposed depending on the local status as well as the age and general condition of the patient. A melanocytic iris nevus is usually observed until documented progression is identified. In this case, radiotherapy or surgical resection is generally performed. Cataract, glaucoma and limbal stem cell deficiency are usually secondary to radiotherapy, while incomplete tumor excisions, which could lead to recurrence, hemorrhage, vitreous loss, dislocated lens, iridocyclitis, macular edema, retinal detachment, glaucoma and cataract, are related to surgical resection. In some cases, a combination of radiotherapy and surgery is used. Conservative treatment is an efficient alternative to enucleation and allows good local tumor control.

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.

Intravitreal Dexamethasone Implant as a Sustained Release Drug Delivery Device for the Treatment of Ocular Diseases: A Comprehensive Review of the Literature

Drug delivery into the vitreous chamber remains a great challenge in the pharmaceutical industry due to the complex anatomy and physiology of the eye. Intravitreal injection is the mainstream route of drug administration to the posterior segment of the eye. The purpose of this review is to assess the current literature about the widening use of the intravitreal 0.7 mg dexamethasone (Dex) implant, and to provide a comprehensive collection of all the ocular disorders that benefit from Dex administration. Although anti-vascular endothelial growth-factors (VEGFs) have been largely indicated as a first-choice level, the Dex implant represents an important treatment option, especially in selected cases, such as vitrectomized eyes or patients in whom anti-VEGF failed or are contraindicated. In this article, the safety profile as well as the list of the possible complications related to intravitreal Dex injection are also discussed.

Retinal Vascular Changes in Radiation Maculopathy after Intravitreal Ranibizumab by Optical Coherence Tomography Angiography

In this prospective study, we investigated the structural and vascular retinal changes at baseline and after Ranibizumab injections at the last follow up to one year in patients affected by Radiation Maculopathy (RM) after plaque brachytheraphy in choroidal melanoma, using Spectral Domain Optical Coherence Tomography (SD-OCT) and OCT Angiography (OCTA). A total of 40 eyes with RM of 40 patients (18 females, 22 males, mean age 51.9 ± 11 years) that underwent ruthenium-106 plaque brachytherapy were included. All patients received one monthly intravitreal injection of Ranibizumab (Pro Re Nata regimen). We analyzed the Foveal Avascular Zone (FAZ) area, the retinal vessel density (VD) of the superficial capillary plexus (SCP) and of the deep capillary plexus (DCP), using OCTA, and we detected the Central Foveal Thickness (CFT) by SD-OCT at baseline and after treatment. At the last follow up, we found a significant improvement of the CFT (p < 0.001) while OCTA parameters revealed no change in VD of the SCP (p = 0.402), DCP (p = 0.282), and FAZ area (p = 0.255), resulting in a stabilization of the visual acuity (p = 0.210) respect to baseline. The absence of functional improvement, despite the anatomical recovery of the macula, could be due to the absence of improvement in FAZ area and in retinal VD after treatment. OCTA parameters could represent predictive biomarkers to anti-vascular endothelial growth factor (anti-VEGF) intravitreal response and to help to better understand the physiopathological mechanisms of the RM.

Intravitreal aflibercept for the treatment of radiation-induced macular edema after ruthenium 106 plaque radiotherapy for choroidal melanoma

PURPOSE

To assess the efficacy of intravitreal aflibercept in patients suffering from post-radiation macular edema following plaque radiotherapy for choroidal melanoma.

METHODS

This prospective, interventional case series included patients affected by radiation maculopathy (RM) with macular edema secondary to ruthenium-106 plaque brachytherapy for choroidal melanoma. The effect of intravitreal aflibercept on best-corrected visual acuity (BCVA), central foveal thickness (CFT) detected by spectral domain optical coherence tomography (sd-OCT), and Horgan's grading scale of RM was evaluated throughout the 24-month follow-up. Intraocular pressure (IOP) and possible complications were also recorded.

RESULTS

Nine eyes of 9 patients were included. A mean of 4.4 ± 1.2 injections were given over the 24 months. At the end of follow-up, mean BCVA was significantly improved, from 0.9 ± 0.19 logMAR at baseline to 0.56 ± 0.3 logMAR (P = 0.028), and mean CFT was significantly decreased, from 546 ± 123 μm at baseline to 223 ± 34 μm (P < 0.001). Intravitreal aflibercept lowered baseline maculopathy stage as well. No significant change in IOP values and no complications, such as endophthalmitis, was recorded.

CONCLUSION

Intravitreal aflibercept is an effective treatment for patients with radiation-induced macular edema, allowing functional and anatomical improvements to be achieved with a relatively low number of injections.

Retinal crystalline deposits in a patient who received chemotherapy and radiotherapy for nasopharyngeal carcinoma and subsequent anti-VEGF treatment for the bilateral radiation maculopathy

We report the occurrence of intraretinal crystalline deposits in a patient who received several anti-VEGF injections and one session of focal laser treatment for the treatment of radiation retinopathy during the treatment process. She had received three cycles of epirubicin and cisplatin together with radiation therapy seven years prior to detection of the maculopathy. The multimodal imaging features and the possible cause of the retinal crystalline deposits are discussed.