Tolerance of the canine bladder to intraoperative radiation therapy: an experimental study
An experimental study of bladder tolerance to intraoperative radiotherapy (IORT) was designed using a large animal model (adult American Foxhounds, weight 25-30 kg) to access acute and late radiation effects. Dogs were subjected to laparotomy where the bladder was mobilized and IORT was delivered using a 5 cm circular cone through a cystotomy incision with 12 MeV electrons. The bladder trigone including both ureteral orifices and the proximal urethra was irradiated in groups of 3 dogs with doses of 0, 20, 25, 30, 35, and 40 Gy. Dogs were followed clinically with repeat urinalysis, intravenous pyelogram (IVP), and cystometrogram at 1 month and then Q6 months for up to 4 years. One dog from each dose group was sacrificed electively at 1 and 2 years, whereas the other dog is being followed clinically for a minimum of 4 years. Complete autopsies were performed with particular attention to genitourinary and pelvic structures. No clinically detectable acute toxicity resulted from IORT to the bladder. Three of 15 IORT dogs (1 each at 25, 35, and 40 Gy) showed obstruction of a ureteral orifice with 2 dogs dying of renal failure secondary to bilateral hydronephrosis within 1-2 years of treatment. The remaining 12 IORT dogs and 3 control dogs have normal repeat IVP's and renal function with up to 4 years of follow-up. Serial cystometry demonstrates no major loss of bladder contractility or volume. At autopsy, histological changes of mucosal thinning and telangiectasia with submucosal fibrosis were confined to the IORT field and appeared dose-related. However, the bladder epithelium remained intact at all doses. The ureterovesical junction in animals receiving 20 Gy showed mild fibrosis of the lamina propria and moderate chronic inflammation. Above 20 Gy, these histological changes at the U-V junction were more pronounced with gross stenosis in 3 animals as predicted by the IVP.
- Research Organization:
- National Cancer Institute, Bethesda, MD (USA)
- OSTI ID:
- 7151968
- Journal Information:
- Int. J. Radiat. Oncol., Biol. Phys.; (United States), Vol. 14:5
- Country of Publication:
- United States
- Language:
- English
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BLADDER
BIOLOGICAL RADIATION EFFECTS
RADIOSENSITIVITY
RADIOTHERAPY
SIDE EFFECTS
ACUTE IRRADIATION
BIOLOGICAL MODELS
CELL FLOW SYSTEMS
DOGS
DOSE-RESPONSE RELATIONSHIPS
EPITHELIUM
RADIATION DOSES
ACUTE EXPOSURE
ANIMAL TISSUES
ANIMALS
BIOLOGICAL EFFECTS
BODY
DOSES
IRRADIATION
MAMMALS
MEDICINE
NUCLEAR MEDICINE
ORGANS
RADIATION EFFECTS
RADIOLOGY
THERAPY
TISSUES
URINARY TRACT
VERTEBRATES
560152* - Radiation Effects on Animals- Animals