TY - JOUR
T1 - Brachial Plexus Tolerance to Single-Session SABR in a Pig Model
AU - Hrycushko, Brian
AU - van der Kogel, Albert J.
AU - Phillips, Lauren
AU - Chhabra, Avneesh
AU - Folkert, Michael R
AU - Sayre, James W.
AU - Vernino, Steven
AU - Hassan-Rezaeian, Nima
AU - Yamada, Yoshiya
AU - Timmerman, Robert
AU - Medin, Paul M.
N1 - Funding Information:
This project was funded by the Cancer Prevention & Research Institute of Texas (RP150356). Disclosures: P.M., B.H., L.P., S.V., and A.C. were investigators and received salary support for this project funded by a research grant paid to their institution (University of Texas Southwestern Medical Center) from the Cancer Prevention & Research Institute of Texas. A.C. serves as a consultant for ICON Medical and Treace Medical Concepts Inc and receives royalties from Jaypee and Wolters. M.F. has received travel funding from Varian Medical Systems and Boston Scientific, Inc. S.V. has served as a consultant for Alterity, Catalyst, and Sage Therapeutics and has received research support from Bio Haven, Genentech, Grifols, and Dysautonomia International. Y.Y. has received payment for speaking engagements from Varian Medical Systems, BrainLab, Vision RT, and the Institute for Medical Education and is on the Chordoma Foundation medical advisory board. R.T. is the principal investigator of clinical research grants paid to his institution (UT Southwestern Medical Center) from Varian Medical Systems, Elekta Oncology, and Accuray, Inc. P.M. has taught radiosurgery courses sponsored by BrainLAB Inc.
Funding Information:
This project was funded by the Cancer Prevention & Research Institute of Texas (RP150356).
Publisher Copyright:
© 2021 Elsevier Inc.
PY - 2022/2/1
Y1 - 2022/2/1
N2 - Purpose: The single-session dose tolerance of the spinal nerves has been observed to be similar to that of the spinal cord in pigs, counter to the perception that peripheral nerves are more tolerant to radiation. This pilot study aims to obtain a first impression of the single-session dose-response of the brachial plexus using pigs as a model. Methods and Materials: Ten Yucatan minipigs underwent computed tomography and magnetic resonance imaging for treatment planning, followed by single-session stereotactic ablative radiotherapy. A 2.5-cm length of the left-sided brachial plexus cords was irradiated. Pigs were distributed in 3 groups with prescription doses of 16 (n = 3), 19 (n = 4), and 22 Gy (n = 3). Neurologic status was assessed by observation for changes in gait and electrodiagnostic examination. Histopathologic examination was performed with light microscopy of paraffin-embedded sections stained with Luxol fast blue/periodic acid-Schiff and Masson's trichrome. Results: Seven of the 10 pigs developed motor deficit to the front limb of the irradiated side, with a latency from 5 to 8 weeks after irradiation. Probit analysis of the maximum nerve dose yields an estimated ED50 of 19.3 Gy for neurologic deficit, but the number of animals was insufficient to estimate 95% confidence intervals. No motor deficits were observed at a maximum dose of 17.6 Gy for any pig. Nerve conduction studies showed an absence of sensory response in all responders and absent or low motor response in most of the responders (71%). All symptomatic pigs showed histologic lesions to the left-sided plexus consistent with radiation-induced neuropathy. Conclusions: The single-session ED50 for symptomatic plexopathy in Yucatan minipigs after irradiation of a 2.5-cm length of the brachial plexus cords was determined to be 19.3 Gy. The dose-response curve overlaps that of the spinal nerves and the spinal cord in the same animal model. The relationship between the brachial plexus tolerance in pigs and humans is unknown, and caution is warranted when extrapolating for clinical use.
AB - Purpose: The single-session dose tolerance of the spinal nerves has been observed to be similar to that of the spinal cord in pigs, counter to the perception that peripheral nerves are more tolerant to radiation. This pilot study aims to obtain a first impression of the single-session dose-response of the brachial plexus using pigs as a model. Methods and Materials: Ten Yucatan minipigs underwent computed tomography and magnetic resonance imaging for treatment planning, followed by single-session stereotactic ablative radiotherapy. A 2.5-cm length of the left-sided brachial plexus cords was irradiated. Pigs were distributed in 3 groups with prescription doses of 16 (n = 3), 19 (n = 4), and 22 Gy (n = 3). Neurologic status was assessed by observation for changes in gait and electrodiagnostic examination. Histopathologic examination was performed with light microscopy of paraffin-embedded sections stained with Luxol fast blue/periodic acid-Schiff and Masson's trichrome. Results: Seven of the 10 pigs developed motor deficit to the front limb of the irradiated side, with a latency from 5 to 8 weeks after irradiation. Probit analysis of the maximum nerve dose yields an estimated ED50 of 19.3 Gy for neurologic deficit, but the number of animals was insufficient to estimate 95% confidence intervals. No motor deficits were observed at a maximum dose of 17.6 Gy for any pig. Nerve conduction studies showed an absence of sensory response in all responders and absent or low motor response in most of the responders (71%). All symptomatic pigs showed histologic lesions to the left-sided plexus consistent with radiation-induced neuropathy. Conclusions: The single-session ED50 for symptomatic plexopathy in Yucatan minipigs after irradiation of a 2.5-cm length of the brachial plexus cords was determined to be 19.3 Gy. The dose-response curve overlaps that of the spinal nerves and the spinal cord in the same animal model. The relationship between the brachial plexus tolerance in pigs and humans is unknown, and caution is warranted when extrapolating for clinical use.
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U2 - 10.1016/j.ijrobp.2021.09.029
DO - 10.1016/j.ijrobp.2021.09.029
M3 - Article
C2 - 34597718
AN - SCOPUS:85118739194
SN - 0360-3016
VL - 112
SP - 565
EP - 571
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 2
ER -