Radiology, Vol 185, 71-76, Copyright © 1992 by Radiological Society of North America
Optic neuropathy after irradiation of meningioma
BJ Goldsmith, SA Rosenthal, WM Wara and DA Larson
Department of Radiation Oncology, University of California, San Francisco 94143-0226.
Radiation-induced optic neuropathy (RON) is a rare and catastrophic
complication of currently employed radiation therapy regimens for
meningiomas that have been partially resected and sampled for biopsy.
Between 1972 and 1989, 49 patients received postoperative irradiation for
partially resected or biopsy sampled meningiomas, with the optic nerve
within the treatment field. One patient experienced RON. The latency period
for this case was 23 months. A review of the literature disclosed few cases
of RON after treatment for meningioma; however, 42 cases of RON have been
reported after radiation therapy for other lesions. The authors constructed
two approaches to predict optic nerve radiation tolerance. The first is
modeled on a previous proposal for a neural tissue nominal standard dose
term and enabled accurate prediction of safe treatment regimens and risk of
RON. This approach compared favorably with previously employed nominal
standard dose terms. The second approach, based on the linear-quadratic
model, proved unsuccessful due to its failure to achieve statistical
significance.
