Retinal Oxygen Function After Radiation Therapy

Changes in Regional Retinal Oxygen Extraction and Function After Radiation Therapy

The investigators propose using retinal oximetry to assess for abnormalities in regional retinal oxygen consumption in previously- irradiated patients, and relate these abnormalities to changes in regional retinal function (i.e. visual field abnormalities). Since different regions of retina receive different radiation doses, the investigators will assess for a dose response as well.

Study Overview

• Status: Completed
• Conditions: A History of Radiation Therapy for a Tumor in the Vicinity of the Retina(s)

Detailed Description

Radiation therapy (RT) is a common treatment for patients with cancers of the sinonasal area, orbit, skull base, nasopharynx, and brain. Because of the close proximity of these targets to the eyes, the retina is often incidentally and unavoidably irradiated. As a result, some patients develop radiation retinopathy and possibly vision loss. Clinicopathologic studies suggest similar microvascular mechanisms for both radiation- and diabetic retinopathy: small vessel occlusion and ischemia that can lead to neovascularization, increased capillary permeability, and visual loss in the regions of retina perfused by damaged vasculature. UNC has a novel, non-invasive retinal imaging technology called a Retinal Oximeter which measures hemoglobin oxygen saturation of retinal vessels. The difference in oxygen saturation between a retinal arteriole and venule pair reflects the oxygen consumption of the retinal region supplied by that vessel pair.

• Study Type: Observational
• Enrollment (Actual): 32

Contacts and Locations

Study Locations

• United States
  • North Carolina
    • Chapel Hill, North Carolina, United States, 27599
      • Department of Radiation Oncology Clinic

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 99 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Adult patients with a history of radiation therapy for a tumor in the vicinity of the retina(s) at the Department of Radiation Oncology, UNC-CH.

Description

Inclusion Criteria:

1. ≥ 18 years of age at the time of radiation therapy (no upper age limit)
2. History of radiation therapy delivered at UNC-CH or Rex Hospital to the vicinity of the retina(s) ≥ 2 months prior to enrollment
3. Estimated average dose to at least one quadrant of one retina ≥ 30 Gy

Exclusion Criteria:

1. History of diabetes, retinal vascular occlusions, glaucoma, retinitis pigmentosa, occipital stroke or any other ophthalmologic or systemic problem that may confound visual field results.
2. Residual tumor within the visual pathway: retina, optic nerves, optic chiasm, optic radiations and brain.

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Abnormalities in regional retinal oxygen extraction after incidental irradiation of the retina.	To identify abnormalities in regional retinal oxygen extraction in patients who have had previous incidental irradiation of the retina.	2 months
Prevalence of vision loss in patients with previous incidental irradiation of the retina	To determine the prevalence of regional retinal dysfunction (i.e. vision loss) in patients with previous incidental irradiation of the retina.	2 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in retinal oxygen extraction compared to radiation dose	To correlate changes in retinal oxygen extraction to radiation dose.	2 months
Vision loss amount versus radiation dose.	To correlate retinal dysfunction (i.e. vision loss) to radiation dose.	2 months
Changes in retinal oxygen extraction as compared to vision loss.	To correlate changes in retinal oxygen extraction to retinal dysfunction (i.e. vision loss).	2 months

Collaborators and Investigators

• Sponsor: UNC Lineberger Comprehensive Cancer Center
• Collaborators: UNC Translational and Clinical Sciences (Tracs)
• Investigators: Principal Investigator: Bhishamjit Chera, MD, Department of Radiation Oncology, University of North Carolina Chapel Hill

Study record dates

Study Major Dates

• Study Start: March 1, 2011
• Primary Completion (Actual): July 1, 2015
• Study Completion (Actual): May 4, 2017

Study Registration Dates

• First Submitted: January 13, 2014
• First Submitted That Met QC Criteria: January 21, 2014
• First Posted (Estimate): January 23, 2014

Study Record Updates

• Last Update Posted (Actual): August 28, 2019
• Last Update Submitted That Met QC Criteria: August 27, 2019
• Last Verified: May 1, 2017

More Information

Terms related to this study

• Keywords: Sinus/nasal cancer
• Other Study ID Numbers: LCCC 1019