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doxorubicin or to metronomic chemotherapy may be seen.
There are three specific companion animal oral tumours that bear separate consideration.
• Feline oral SCC - these are often locally extensive at diagnosis, and if not surgical are very resistant
to treatment, with median survival times of a few months. Even with surgery, recurrence is common, though for small tumours that can be treated with mandibulectomy and adjuvant radiation, survival times may be improved. RT alone does not appear to be effective in most cases. There is one small study evaluating systemic bleomycin chemotherapy along with radiation and surgery where outcomes may have been better, and toceranib (+/- NSAIDs +/- metronomic chemotherapy) may be of benefit
in some cats. The use of NSAIDs is recommended based on COX expression in feline SCC for potential anti-tumour effects as well as for analgesia.
• Canine tonsillar SCC - unlike non-tonsillar oral SCC (with the possible exception of lingual SCC), tonsillar SCC is highly metastatic and aggressive in dogs. Often the diagnosis is made from a metastatic
lymph node which is externally visible, rather than the primary tumour in the tonsil. Survival times are generally short (months), even with treatment, though combinations of chemotherapy (usually carboplatin) and radiation therapy may achieve reasonable palliation. However, in those where the disease is diagnosed early (no metastasis, one tonsil affected), prolonged survival may be possible with treatment.
• Canine hi-low (histologically low grade biologically high grade) FSA - a subset of canine oral FSA will appear non-aggressive (low grade sarcoma or even fibroma or reactive fibrous tissue) and yet have very aggressive behaviour with rapid local growth and extensive tissue invasion. This syndrome seems to be more common in the maxilla of large breed dogs. If amenable to aggressive therapy, outcomes can still be favourable.
Vail DM, Withrow SJ, editors. Withrow and McEwen’s Small Animal Clinical Oncology (5th edition) W.B. Saunders, Philadelphia, 2012 is recommended as a general resource
C. Ward1
1University of Georgia College of Veterinary Medicine, Small Animal Medicine and Surgery, Athens, USA
Cynthia R. Ward, VMD, PhD, DACVIM (SAIM) University of Georgia College of Veterinary Medicine Athens, GA 30602 USA
Hyperadrenocorticism (HAC) is a common endocrinopathy in middle to older aged dogs.
Clinical signs to make the clinician suspicious of hyperadrenocorticism include many “p’s” polyphagia, polyuria/polydipsia, pyoderma, pot bellied appearance, and persistent urinary tract infections. Physical examination findings include hepatomegaly, truncal obesity, muscle wasting, panting, bilaterally symmetrical alopecia, thin, hyperpigmented skin, calcinosis cutis,
and lipid deposits.Dogs get HAC in 2 ways: pituitary tumors (85%) and adrenal tumors (15%). Both produce
an excess of cortisol that causes the disease entity. Three screening tests are available. The urine cortisol:creatinine ratio is very sensitive (100%) although not specific. Therefore if the urine cortisol:creatinine ratio is positive, another screening test will be necessary in order to diagnose the disease. A second screening test for HAC is the low dose dexamethasone suppression test. This should be to go to test unless there is significant concurrent disease such as diabetes mellitus. It is sensitive (89-92%) but with a decrease in specificity (75%). It is least specific in animals with concurrent disease. A third screening test for HAC is the ACTH Stimulation Test. It is less sensitive (75-83%) than the low dose dexamethasone test but it is more specific (85%).
It is more specific in animals with concurrent disease
and recommended for use in dogs with concurrent diabetes mellitus to decrease the possibility of a false positive response. The practitioner measures cortisol before and 60 min after injection of 5 ug/kg synthetic ACTH (cortrosyn). In diabetic patients, the owner should feed and administer insulin as usual. A simultaneous glucose curve should be performed in conjuction with the ACTH-stimulation test to ensure that the animal has blood glucose within the optimal range during testing. If ACTH-stimulation testing supports HAC, then treatment should be initiated. If HAC is still suspected but is not supported by the ACTH-stimulation test, then the test can be repeated 2-4 weeks later.
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