Chorioretinal Side Effects of Therapeutic Ocular Irradiation: A Multimodal Imaging Approach

Radiation retinopathy following episcleral brachytherapy for intraocular tumors: Current treatment options

Radiation retinopathy (RR) and radiation maculopathy (RM) can occur as a result of uveal melanoma radiation treatment and after irradiation of other head and neck extraocular tumors, even with precise targeting techniques, such as stereotactic or proton beam radiotherapy. This review provides an overview of the current understanding of potential radiation damage to ocular tissues, and how recent developments in ophthalmic multimodal imaging techniques and treatment modalities have improved managing options. Several treatment strategies have been employed so far for the management of RR, including laser photocoagulation, intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents or glucocorticosteroids and surgery. The use of intravitreal anti-VEGFs or dexamethasone implants have significantly altered the final visual outcome for uveal melanoma patients. As a prophylaxis, a few different strategies were proposed, but still there is a lack of large randomized clinical trials supporting these approaches and clear clinical guidelines for daily practice. Early detection and proper treatment are crucial in preventing or reducing vision loss, and improving patients' quality of life. Close monitoring and timely intervention are essential for successful management.

RADIATION MACULOPATHY IS ANTICIPATED BY OCT HYPERREFLECTIVE RETINAL FOCI: A Large, Prospective, Confirmation Study

PURPOSE

To investigate, by means of spectral domain optical coherence tomography, retinal reflectivity changes as an early biomarker anticipating radiation-induced macular edema (ME) in patients treated by iodine-125 (I-125) brachytherapy.

METHODS

Thirty patients planned for I-125 brachytherapy because of uveal melanoma were prospectively included and followed every 4 months for five years. Reflectivity alterations, namely hyperreflective retinal foci, were characterized and counted by two independent masked examiners by means of spectral domain optical coherence tomography imaging. Hyperreflective retinal foci were defined as discrete intraretinal reflectivity changes ≤30 µm, with reflectivity similar to nerve fiber layer and without back shadowing.

RESULTS

Macular edema occurred in 17 patients (24.2 ±15.1 months) (group 1) after irradiation. Thirteen patients showed no signs of ME at the 5-year follow-up (group 2). The number of hyperreflective retinal foci was statistically higher in sequential visits until the evidence of ME in group 1 vs group 2 (P < 0.0001). In group 1, hyperreflective retinal foci at the follow-up before the evidence of ME were significantly related to the OCT central subfield thickness at ME appearance (P = 0.0002, r2=0.6129). The intergrader agreement was almost perfect (intraclass correlation coefficient = 0.80).

CONCLUSION

Hyperreflective retinal foci may be considered as an early in vivo imaging biomarker of retinal inflammatory response to ocular irradiation, anticipating the development of radiation maculopathy.

Histopathologic and MR Imaging Appearance of Spontaneous and Radiation-Induced Necrosis in Uveal Melanomas: Initial Results

Simple Summary

Uveal melanomas may undergo necrosis, both spontaneously or following radiotherapy. Nowadays radiotherapy is the preferred treatment, whereas enucleation of the eye is used in selected cases. In order to differentiate the effects of radiotherapy from spontaneous degenerative changes in uveal melanomas, we compared the appearance of necrosis, both from a histopathological point of view and from the perspective of MR imaging, in two groups of patients with uveal melanoma: a group who had undergone previous proton beam radiotherapy (secondary enucleation); a control group who had undergone enucleation without any previous radiotherapy treatment (primary enucleation). Irradiated and nonirradiated uveal melanomas differ on the basis of the histological appearance, the MR imaging appearance and the distribution of necrosis. We hope that the findings we observed could be extended to all patients with uveal melanomas treated with radiotherapy, and may enhance the accuracy of radiologists in evaluating MR examinations after radiotherapy.

Abstract

Necrosis in uveal melanomas can be spontaneous or induced by radiotherapy. The purpose of our study was to compare the histopathologic and MRI findings of radiation-induced necrosis of a group of proton beam-irradiated uveal melanomas with those of spontaneous necrosis of a control group of patients undergoing primary enucleation. 11 uveal melanomas who had undergone proton beam radiotherapy, MRI and secondary enucleation, and a control group of 15 untreated uveal melanomas who had undergone MRI and primary enucleation were retrospectively identified. Within the irradiated and nonirradiated group, 7 and 6 eyes with histological evidence of necrosis respectively, were furtherly selected for the final analysis; the appearance of necrosis was assessed at histopathologic examination and MRI. Irradiated melanomas showed a higher degree of necrosis as compared with nonirradiated tumors. Irradiated and nonirradiated lesions differed based on the appearance and distribution of necrosis. Irradiated tumors showed large necrotic foci, sharply demarcated from the viable neoplastic tissue; nonirradiated tumors demonstrated small, distinct foci of necrosis. Radiation-induced necrosis, more pigmented than surrounding viable tumor, displayed high signal intensity on T1-weighted and low signal intensity on T2-weighted images. The hemorrhagic/coagulative necrosis, more prevalent in nonirradiated tumors (4 out of 6 vs. 1 out of 7 cases), appeared hyperintense on T2-weighted and hypointense on T1-weighted images. Our study boosts the capability to recognize radiation-induced alterations in uveal melanomas at MRI and may improve the accuracy of radiologists in the evaluation of follow-up MR examination after radiotherapy.

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.

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.