Radiation Retinopathy: Detection and Management Strategies

A Novel Predictive Model Utilizing Retinal Microstructural Features for Estimating Survival Outcome in Patients with Glioblastoma

Glioblastoma is a highly aggressive brain tumor with poor prognosis despite surgery and chemoradiation. The visual sequelae of glioblastoma have not been well characterized. This study assessed visual outcomes in glioblastoma patients through neuro-ophthalmic exams, imaging of the retinal microstructures/microvasculature, and perimetry. A total of 19 patients (9 male, 10 female, average age at diagnosis 69 years) were enrolled. Best-corrected visual acuity ranged from 20/20-20/50. Occipital tumors showed worse visual fields than frontal tumors (mean deviation - 14.9 and - 0.23, respectively, p < 0.0001). Those with overall survival (OS) < 15 months demonstrated thinner retinal nerve fiber layer and ganglion cell complex (p < 0.0001) and enlarged foveal avascular zone starting from 4 months post-diagnosis (p = 0.006). There was no significant difference between eyes ipsilateral and contralateral to radiation fields (average doses were 1370 cGy and 1180 cGy, respectively, p = 0.42). A machine learning algorithm using retinal microstructure and visual fields predicted patients with long (≥ 15 months) progression free and overall survival with 78% accuracy. Glioblastoma patients frequently present with visual field defects despite normal visual acuity. Patients with poor survival duration demonstrated significant retinal thinning and decreased microvascular density. A machine learning algorithm predicted survival; further validation is warranted.

Neurological complications of modern radiotherapy for head and neck cancer

Radiotherapy is one of the mainstay treatment modalities for the management of non-metastatic head and neck cancer (HNC). Notable improvements in treatment outcomes have been observed in the recent decades. Modern radiotherapy techniques, such as intensity-modulated radiotherapy and charged particle therapy, have significantly improved tumor target conformity and enabled better preservation of normal structures. However, because of the intricate anatomy of the head and neck region, multiple critical neurological structures such as the brain, brainstem, spinal cord, cranial nerves, nerve plexuses, autonomic pathways, brain vasculature, and neurosensory organs, are variably irradiated during treatment, particularly when tumor targets are in close proximity. Consequently, a diverse spectrum of late neurological sequelae may manifest in HNC survivors. These neurological complications commonly result in irreversible symptoms, impair patients' quality of life, and contribute to a substantial proportion of non-cancer deaths. Although the relationship between radiation dose and toxicity has not been fully elucidated for all complications, appropriate application of dosimetric constraints during radiotherapy planning may reduce their incidence. Vigilant surveillance during the course of survivorship also enables early detection and intervention. This article endeavors to provide a comprehensive review of the various neurological complications of modern radiotherapy for HNC, summarize the current incidence data, discuss methods to minimize their risks during radiotherapy planning, and highlight potential strategies for managing these debilitating toxicities.

INDOCYANINE GREEN ANGIOGRAPHY-GUIDED PHOTOCOAGULATION OF LARGE MICROVASCULAR ABNORMALITIES ("TELCAPS") IN A PATIENT WITH PERSISTENT MACULA EDEMA IN THE CONTEXT OF RADIATION RETINOPATHY

PURPOSE

The purpose of this report is to describe a patient with radiation retinopathy who responded to indocyanine green angiography (ICGA)-guided photocoagulation as treatment for persistent macula edema secondary to TelCaps, a newly defined type of large microvascular abnormality.

METHODS

Retrospective case report.

RESULTS

A 40-year-old man with a history of bilateral retinoblastoma and right enucleation presented with decreased vision in the left eye secondary to macula edema. Examination revealed radiation retinopathy with a cluster of ICGA-avid large microaneurysms temporal to the macula. The patient did not respond to treatment with intravitreal bevacizumab or triamcinolone. Complete resolution of macula edema was demonstrated after two rounds of ICGA-guided focal photocoagulation to the aforementioned microaneurysm cluster. No subsequent or adjunctive intravitreal injections of anti-VEGF were required, and there was no recurrence of the TelCaps lesions at follow-up to eight years.

CONCLUSION

TelCaps are large microvascular abnormalities with high affinity for ICG. These lesions may not have been recognized because of difficulties in their detection on routine examination and with investigations including ocular coherence tomography angiogram and fluorescein angiogram. Early evidence supports their role in macula edema that is not responsive to intravitreal injections of anti-VEGF. ICGA-guided photocoagulation of TelCaps lesions can result in resolution of macula edema. To our knowledge, this is the first reported case of TelCaps secondary to radiation retinopathy.

Radiation-induced ophthalmic risks of long duration spaceflight: Current investigations and interventions

PURPOSE

As the average duration of space missions increases, astronauts will experience longer periods of exposure to risks of long duration space flight including microgravity and radiation. The risks from long-term exposure to space radiation remains ill-defined. We review the current literature on the possible and known risks of radiation on the eye (including radiation retinopathy) after long duration spaceflight.

METHODS

A PubMed and Google Scholar search of the English language ophthalmic literature was performed from inception to July 11, 2022. The following search terms were utilized independently or in conjunction to build this manuscript: "Radiation Retinopathy", "Spaceflight", "Space Radiation", "Spaceflight Associated Neuro-Ocular Syndrome", "Microgravity", "Hypercapnia", "Radiation Shield", "Cataract", and "SANS". A concise and selective approach of references was conducted in including relevant original studies and reviews.

RESULTS

A total of 65 papers were reviewed and 47 papers were included in our review.

CONCLUSION

We discuss the potential and developing countermeasures to mitigate these radiation risks in preparation for future space exploration. Given the complex nature of space radiation, no single approach will fully reduce the risks of developing radiation maculopathy in long-duration spaceflight. Understanding and appropriately overcoming the risks of space radiation is key to becoming a multi-planetary species.

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.

Radiotherapy in Uveal Melanoma: A Review of Ocular Complications

Uveal melanoma represents the most prevalent form of primary malignant intraocular tumor in adults. Historically, enucleation was considered the gold-standard approach in the treatment of uveal melanoma. Currently, radiotherapy is the most commonly used therapy, aiming at a better quality of life. However, radiotherapy can result in several ocular complications, some of which may be vision-threatening. Radiation-induced dry eye, scleral necrosis, cataract, rubeosis iridis, neovascular glaucoma, radiation retinopathy, maculopathy, and optic neuropathy are the most common complications. This article aims to summarize the current literature regarding the ocular complications after radiotherapy, as well as their clinical features, risk factors, and management strategies. A thorough understanding of these issues is crucial for ophthalmologists and oncologists to provide optimal patient care, improve visual outcomes, and minimize long-term complications.

Intratumoral bacteria in uveal melanoma: A case report

Purpose

Intratumoral bacteria and their potential application to cancer immunotherapy have been a topic of interest in recent studies. To our knowledge, bacteria in uveal melanoma have not been previously reported.

Observations

We describe a patient with a large choroidal melanoma, measuring 18 × 16 mm in basal dimension and 15 mm in ultrasonographic thickness, managed by plaque brachytherapy. At the time of plaque removal, a prophylactic scleral patch graft was placed to protect from anticipated scleral necrosis. Progressive ocular ischemia led to a blind and painful eye. The enucleated eye demonstrated an extensively necrotic and heavily pigmented mushroom-shaped regressed cilichoroidal mass deep to the scleral patch graft. Numerous Gram-positive cocci were noted within the regressed uveal melanoma and the adjacent sclera.

Conclusions and Importance

This case highlights the fact that regressed uveal melanomas can contain intra-tumoral bacteria.