Efficacy of cobalt 60 radiotherapy in dogs with pituitary-dependent hyperadrenocorticism

Marielle M. C. Goossens From the Veterinary Medical Teaching Hospital (Goossens) and Departments of Medicine and Epidemiology (Feldman) and Surgical and Radiological Sciences (Theon, Koblik), School of Veterinary Medicine, University of California, Davis, CA 95616-8734.

Search for other papers by Marielle M. C. Goossens in
Current site
Google Scholar
PubMed
Close
 DVM
,
Edward C. Feldman From the Veterinary Medical Teaching Hospital (Goossens) and Departments of Medicine and Epidemiology (Feldman) and Surgical and Radiological Sciences (Theon, Koblik), School of Veterinary Medicine, University of California, Davis, CA 95616-8734.

Search for other papers by Edward C. Feldman in
Current site
Google Scholar
PubMed
Close
 DVM
,
Alain P. Theon From the Veterinary Medical Teaching Hospital (Goossens) and Departments of Medicine and Epidemiology (Feldman) and Surgical and Radiological Sciences (Theon, Koblik), School of Veterinary Medicine, University of California, Davis, CA 95616-8734.

Search for other papers by Alain P. Theon in
Current site
Google Scholar
PubMed
Close
 Dr med vet, PhD
, and
Philip D. Koblik From the Veterinary Medical Teaching Hospital (Goossens) and Departments of Medicine and Epidemiology (Feldman) and Surgical and Radiological Sciences (Theon, Koblik), School of Veterinary Medicine, University of California, Davis, CA 95616-8734.

Search for other papers by Philip D. Koblik in
Current site
Google Scholar
PubMed
Close
 DVM, MS

Click on author name to view affiliation information

Objective

To determine efficacy of cobalt 60 radiotherapy in dogs with pituitary-dependent hyperadreno-corticism (PDH) that have detectable tumors but no neurologic abnormalities.

Design

Case series.

Animals

6 dogs with PDH that had a detectable pituitary mass on magnetic resonance images.

Procedure

Radiation was delivered in 11 fractions during a 3.5-week period for a total dose of 44 Gy. Clinical signs were evaluated, a urinalysis and ACTH stimulation test were performed, and urine cortisol-to-creatinine ratio and plasma endogenous ACTH concentration were measured before, immediately after, and 1, 3, 6, 9, and 12 months after radiotherapy. Magnetic resonance imaging was repeated 1 year after radiotherapy.

Results

Clinical signs of hyperadrenocorticism resolved in 3 dogs but recurred in 2 of the 3. Clinical condition of 2 dogs improved but did not return to normal. One dog did not improve. Results of ACTH stimulation tests and urine cortisol-to-creatinine ratios correlated with clinical signs. Plasma endogenous ACTH concentration transiently decreased in all 6 dogs. One year after radiotherapy, size of tumors was decreased by 25% in 2 dogs; in the other 4 dogs, tumors could no longer be detected. None of the dogs developed neurologic abnormalities. Adverse effects of radiotherapy were mild.

Clinical Implications

Radiotherapy did not result in adequate control of clinical signs of hyperadrenocorticism in 5 of 6 dogs, but size of pituitary tumors was dramatically reduced. Thus, it may be reasonable to recommend radiotherapy in dogs with PDH that have pituitary tumors for which greatest vertical height is 8 mm or more. (J Am Vet Med Assoc 1998; 212:374-376)

Objective

To determine efficacy of cobalt 60 radiotherapy in dogs with pituitary-dependent hyperadreno-corticism (PDH) that have detectable tumors but no neurologic abnormalities.

Design

Case series.

Animals

6 dogs with PDH that had a detectable pituitary mass on magnetic resonance images.

Procedure

Radiation was delivered in 11 fractions during a 3.5-week period for a total dose of 44 Gy. Clinical signs were evaluated, a urinalysis and ACTH stimulation test were performed, and urine cortisol-to-creatinine ratio and plasma endogenous ACTH concentration were measured before, immediately after, and 1, 3, 6, 9, and 12 months after radiotherapy. Magnetic resonance imaging was repeated 1 year after radiotherapy.

Results

Clinical signs of hyperadrenocorticism resolved in 3 dogs but recurred in 2 of the 3. Clinical condition of 2 dogs improved but did not return to normal. One dog did not improve. Results of ACTH stimulation tests and urine cortisol-to-creatinine ratios correlated with clinical signs. Plasma endogenous ACTH concentration transiently decreased in all 6 dogs. One year after radiotherapy, size of tumors was decreased by 25% in 2 dogs; in the other 4 dogs, tumors could no longer be detected. None of the dogs developed neurologic abnormalities. Adverse effects of radiotherapy were mild.

Clinical Implications

Radiotherapy did not result in adequate control of clinical signs of hyperadrenocorticism in 5 of 6 dogs, but size of pituitary tumors was dramatically reduced. Thus, it may be reasonable to recommend radiotherapy in dogs with PDH that have pituitary tumors for which greatest vertical height is 8 mm or more. (J Am Vet Med Assoc 1998; 212:374-376)

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 306 306 118
PDF Downloads 34 34 4
Advertisement