OCT-A evaluation of radiation vasculopathy following slotted plaque brachytherapy

Retinal Microstructural Changes Reflecting Treatment-Associated Cognitive Dysfunction in Patients with Lower-Grade Gliomas

Purpose

To determine whether microstructural retinal changes, tumor features, and apolipoprotein E (APOE) ε4 polymorphism are correlated with clinically detectable treatment-associated cognitive dysfunction (TACD) in patients with lower-grade gliomas.

Design

Cohort study.

Participants and Controls

Sixteen patients with lower-grade glioma at a United States academic ophthalmology department between January 2021 and November 2023. Normal controls were recruited from convenient sampling.

Methods

Montreal Cognitive Assessment (MoCA) scores and retinal changes were assessed in 6-month intervals. Apolipoprotein E genotyping was performed, and tumor details were recorded. Partial least-squares discriminant (PLSD) model was established to evaluate the association between TACD with APOE genotype, ophthalmic, and tumor features.

Main Outcome Measures

The main outcome measure was cognitive status as measured by the MoCA score and analyzed in relation to ophthalmic measurements, tumor features, and APOE genotype.

Results

Median time to first eye examination was 34 months (2-266) from tumor diagnosis and 23 months (0-246) from radiation. Nine patients (56%) had abnormal cognition (MoCA <26/30). Montreal Cognitive Assessment scores were significantly worse in patients with temporal (22 ± 7.2) than frontal lobe tumors (26 ± 3.1, P = 0.02) and those with oligodendrogliomas (22 ± 4.1) than astrocytomas (26 ± 3.6, = 0.02). Patients with TACD had significant radial peripapillary capillary density loss (45% ± 4.6) compared with those with normal cognition (49% ± 2.6, P = 0.02). A PLSD model correlated MoCA scores with retinal nerve fiber thickness, intraocular pressure, foveal avascular zone, best-corrected visual acuity, months since first diagnosis, and tumor pathology (oligodendroglioma or not). Using these features, the model identified patients with TACD with 77% accuracy. Apolipoprotein E genotyping showed: 2 ε2/ε3 (13%), 10 ε3/ε3 (63%), and 1 ε3/ε4 (6%).

Conclusions

Retinal microstructural changes may serve as biomarkers for TACD in patients with lower-grade gliomas. Temporal lobe tumors and oligodendrogliomas may increase susceptibility to TACD. Utilization of retinal markers may enhance TACD diagnosis, progression monitoring, and inform management of lower-grade patients with glioma. A larger study with serial eye examinations is warranted to evaluate the role of APOE ε4 and develop a predictive model.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Efficacy of Prophylactic Anti-VEGF in Preventing Radiation Retinopathy: A Systematic Review and Meta-Analysis

Background

In patients predisposed to radiation retinopathy (RR), administration of therapy after apparent clinical signs and symptoms are considered too late, resulting in substantial vision loss and blindness. Early initiation of anti-vascular endothelial growth factor (anti-VEGF) might serve as a strategy to slow disease progression and prolong good eyesight.

Objective

To evaluate the efficacy of prophylactic anti-VEGF in preventing RR and preserving vision in patients at high risk of radiation-induced vision loss.

Methods

A systematic literature search was performed from inception to 4 June 2023 using Cochrane Library, EMBASE, PubMed (MEDLINE), and Scopus. Eligible studies were clinical trials and observational studies investigating the incidence of radiation maculopathy (RM), radiation optic neuropathy (RON), moderate vision loss (loss of more than or equal to 3 lines of baseline visual acuity [VA]) and final VA, whether good (20/40 or better) or poor (20/200 or worse), following prophylactic anti-VEGF. Three reviewers independently conducted article screening, data extraction and risk of bias assessment. Random effects models were used to determine the cumulative effects of each outcome.

Results

Four studies (one clinical trial and three observational studies), involving 2109 patients, were included in our analysis. Across all studies, there were significant reductions in the events of RM (pooled odds ratio [OR] 0.50; 95% CI, 0.34-0.74; p = 0.001), RON (pooled OR 0.62; 95% CI, 0.42-0.90; p = 0.012) and poor final VA (pooled OR 0.50; 95% CI, 0.37-0.68; p = 0.003). The association of moderate vision loss and good final VA with the use of prophylactic anti-VEGF between the groups was unclear owing to the high level of heterogeneity.

Conclusion

Prophylactic anti-VEGF therapy might delay RM and RON, preventing high-risk patients from developing poor VA by approximately 50%. However, this evidence should be interpreted with caution because of its low level of certainty. Future robust studies are warranted to confirm this finding.

Early anti-VEGF treatment for radiation maculopathy and optic neuropathy: lessons learned

Radiation therapy has saved both sight and life for eye cancer patients. The most common methods include ophthalmic plaque brachytherapy and external beam techniques. However, subsequent dose-dependent radiation vasculopathy invariably occurs within and around the targeted zone. In 2006, Finger discovered that periodic intravitreal anti-vascular endothelial growth factor (anti-VEGF) bevacizumab could reverse and suppress intraocular radiation vasculopathy. At first, it was administered at the onset of radiation-related vision loss. Though bevacizumab induced regression of macular oedema, retinal haemorrhages and cotton-wool infarcts, most patients were left with residual retinal damage, manifest as metamorphopsia and loss of vision. These results led to earlier and earlier anti-VEGF interventions: first after signs of progressive radiation retinopathy, and then for signs of radiation maculopathy, and finally for high-risk eyes with no clinical signs of retinopathy. Earlier initiation of intravitreal anti-VEGF therapy typically resulted in greater restoration and preservation of macular anatomy, reductions of retinal haemorrhages, resolution of cotton-wool spots and vision preservation. Recent research on optical coherence tomography angiography (OCT-A) has revealed that radiation vasculopathy occurs prior to clinical ophthalmic signs or symptoms. Therefore, it seemed reasonable to consider treating high-risk patients (considered certain to eventually develop radiation maculopathy) to prevent or delay vision loss. Herein, we describe the evolution of treatment for radiation maculopathy as well as recent research supporting anti-VEGF treatment of high-risk patients immediately following radiation to maximize vision outcomes.

Optic disc cupping after circumpapillary Pd-103 slotted plaque radiation therapy

OBJECTIVE

To investigate vascular and morphologic optic disc changes after slotted plaque radiation therapy for choroidal melanoma involving the optic disc.

DESIGN

Retrospective cross-sectional study.

PARTICIPANTS

Thirty-nine patients with choroidal melanoma involving the optic nerve.

METHODS

Each melanoma was treated with palladium-103 slotted plaque brachytherapy (incorporating and/or surrounding the optic nerve sheath) between 2005 and 2019. Imaging of the optic nerve before and after radiation allowed for documentation and evaluation of optic nerve pallor and cup-to-disc ratio (CDR) changes. Optical coherence tomography (OCT) CDR measurements and intraocular pressure (IOP) were recorded pretreatment and at follow-up. Of these patients, 22 also had OCT angiography (OCT-A) images with sufficient quality for evaluation of blood vessel density and length. Differences in cup-to-disc measurements were correlated with changes in OCT-A-measured vessel density and length.

RESULTS

Following slotted plaque radiation therapy, there was no significant increase in IOP or optic nerve pallor. OCT and colour photography revealed significant increases (both p < 0.001) in CDR from pretreatment to the last follow-up. Increased CDRs on OCT were significantly correlated to OCT-A-measured change in vessel length (p = 0.027). Similarly, increased CDR ratios on fundus photography were significantly correlated with OCT-A-measured change in vessel density (p = 0.043) and length (p = 0.019).

CONCLUSION

Fundus photography and OCT measurements revealed increased optic disc cupping following slotted plaque radiation therapy. Cupping was associated with OCT-A evidence of synchronous progressive peripapillary vascular occlusion and attenuation. Therefore, slotted plaque radiation-induced peripapillary and papillary ischemia was associated with increased CDR ratios and optic disc cupping.