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Updated: Aug 10, 2026
Rat Model of Photochemically-Induced Posterior Ischemic Optic Neuropathy
Published on: November 29, 2015
Does altered fractionation influence the risk of radiation-induced optic neuropathy?
Niranjan Bhandare1, Alan T Monroe, Christopher G Morris
1Department of Radiation Oncology, Health Science Center, University of Florida College of Medicine, Gainesville, FL 32610, USA.
Purpose:
To analyze the parameters that influence the risk of radiation-induced optic neuropathy (RION) after radiotherapy for head-and-neck tumors.
Methods And Materials:
Between 1964 and 2000, 273 patients with tumors of the nasopharynx, paranasal sinuses, nasal cavity, and hard palate adenoid cystic carcinomas were treated with curative intent and had radiation fields that included the optic nerves and/or chiasm. Patients were followed for at least 1 year after radiotherapy.
Results:
Radiation-induced optic neuropathy developed in 32 eyes of 24 patients (9%). The 5-year rates of freedom from RION according to the total dose and once- vs. twice-daily fractionation were as follows: < or =63 Gy once daily, 95%; < or =63 Gy twice daily, 98%; >63 Gy once daily, 78%; and >63 Gy twice daily, 91%. Multivariate analysis revealed that the total dose affected the risk of RION (p = 0.0047), with patient age (p = 0.0909), once-daily vs. twice-daily fractionation (p = 0.0684), and overall treatment time (p = 0.0972) were marginally significant. The use of adjuvant chemotherapy did not significantly influence the likelihood of developing RION.
Conclusion:
The likelihood of developing RION is primarily influenced by the total dose. Hyperfractionation may reduce the risk of experiencing this complication.
