Effectiveness of fractionated external beam radiation in the inhibition of vascular restenosis.
BACKGROUND
From the clinical oncologic experience, fractionation of the radiation dose offers a better therapeutic window, both with respect to effectiveness and unwanted side effects. Thus, we undertook a pilot study in a rodent model, using a single dose of 15 Gy compared with fractionation schedules of 5 or 10 daily applications of 3 Gy.


METHODS
Using a previously described rat angioplasty model, animals were randomly assigned to one of four groups: unilateral balloon injury, sham irradiation; unilateral balloon injury, bilateral 15 Gy single dose irradiation; unilateral balloon injury, bilateral 3 Gy x 5 daily fractions; or unilateral balloon injury, bilateral 3 Gy x 10 daily fractions.


CONCLUSIONS
All three radiation groups demonstrated a clear inhibition of neointimal hyperplasia. We therefore offer evidence for the effectiveness of fractionated radiation as a means to inhibit vascular restenosis in a rat carotid model. However, the 3 Gy x 5 schedule was less effective than either the 3 Gy x 10 schedule or the 15 Gy single dose. This study must be repeated using longer time points to provide proof of principle.
Department of Radiation Oncology, University of Rochester Medical Center, New York, USA. Jackie_Williams@urmc.rochester.edu
J P
JP
Williams
M
M
Eagleton
E
E
Hernady
M
M
Schell
K
K
Illig
R
R
Green
P
P
Rubin
D000818:Animals; D020212:Carotid Artery Injuries / Q000209:etiology / Q000473:pathology / Q000532:radiotherapy; D016893:Carotid Stenosis / Q000473:pathology / Q000517:prevention & control / Q000532:radiotherapy*; D002404:Catheterization / Q000009:adverse effects; D006801:Humans; D006965:Hyperplasia; D008297:Male; D011879:Radiotherapy Dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D012008:Recurrence