Clinical toxicity of peripheral nerve to intraoperative radiotherapy in a canine model.
OBJECTIVE
The clinical late effects of intraoperative radiotherapy (IORT) on peripheral nerve were investigated in a foxhound model.


METHODS
Between 1982 and 1987, 40 animals underwent laparotomy with intraoperative radiotherapy of doses from 0-75 Gy administered to the right lumbosacral plexus. Subsequently, all animals were monitored closely and sacrificed to assess clinical effects to peripheral nerve. This analysis reports final clinical results of all animals, with follow-up to 5 years.


RESULTS
All animals treated with > or = 25 Gy developed ipsilateral neuropathy. An inverse relationship was noted between intraoperative radiotherapy dose and time to neuropathy, with an effective dose for 50% paralysis (ED50) of 17.2 Gy. One of the animals treated with 15 Gy IORT developed paralysis, after a much longer latency than the other animals.


CONCLUSIONS
Doses of 15 Gy delivered intraoperatively may be accompanied by peripheral neuropathy with long-term follow-up. This threshold is less than that reported with shorter follow-up. The value of ED50 determined here is in keeping with data from other animal trials, and from clinical trials in humans.
Johnstone
P A
PA
Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
DeLuca
A M
AM
Bacher
J D
JD
Hampshire
V A
VA
Terrill
R E
RE
Anderson
W J
WJ
Kinsella
T J
TJ
Sindelar
W F
WF
D000818:Animals; D004285:Dogs; D005500:Follow-Up Studies; D007432:Intraoperative Period; D010243:Paralysis / Q000209:etiology*; D010525:Peripheral Nerves / Q000528:radiation effects*; D010523:Peripheral Nervous System Diseases / Q000209:etiology; D011829:Radiation Dosage; D011878:Radiotherapy / Q000009:adverse effects; D013997:Time Factors