Abstract
Purpose :
Radiation therapy is an effective treatment for a variety of ocular cancers, yet these radiotherapies can damage the retina, resulting in radiation retinopathy (RR) 6 months to 3 years post-radiation. In this post-hoc analysis[ST1] , we monitor and investigate retinal morphological outcomes via spectral-domain optical coherence tomography (SD-OCT), slit lamp, and/or direct ophthalmoscope to identify the most relevant biomarkers related to visual acuity.
Methods :
Forty eyes with active RR were randomly assigned to cohorts A, B, and C for intravitreal ranibizumab (RBZ, 0.5 mg) treatment: (A) monthly RBZ injections for 48 weeks (n = 8), (B) monthly RBZ injections for 48 weeks plus targeted retinal photocoagulation to areas of peripheral retinal ischemia one week after the initial RBZ injection (n = 16), or (C) three consecutive monthly ranibizumab injections followed by as needed monthly RBZ injections (n = 16). At week 52, all cohorts entered a standardized treat-and-extend regimen until week 104. Best-corrected visual acuity and qualitative and quantitative SD-OCT parameters were assessed by frequency, univariate, multiple linear regression, and mixed model analyses.
Results :
There was a significant difference in the presence of retinal hemorrhages at week 24, 48, 72, and 104 (P < 0.0001) and hard exudates at week 48 (P = 0.016) from baseline. A significant difference in the percentage of patients with neovascularization was found between cohorts (P = 0.003); cohort C had a significantly higher mean percentage of incidences of neovascularization (14.4%) compared to both cohorts A (0%) and B (4.01%). No significant differences were found between cohorts for the other graded parameters. Intraretinal cyst vertical size (P < 0.001) and EZ disruption (P = 0.029), were found to be most relevant to visual acuity due to their correlation with visual acuity by univariate analysis, with their significance confirmed in the mixed model (P = 0.001) and multiple linear regression model (P = 0.01), respectively.
Conclusions :
This study helps characterize the course of vision in patients with RR by confirming the relevance of intraretinal vertical cyst size and EZ disruption as morphological biomarkers of poor visual acuity from prior studies. Larger, multicenter studies are needed to fully understand and monitor morphological changes affecting visual acuity changes in RR.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.