Endocrine Tumours Flashcards
What’s the distribution of canine pituitary adenoma, invasive adenoma, and adenocarcinoma on necropsy?
61% = adenoma
33% = invasive adenoma
6% = adenocarcioma
What % of dogs will not have a visible pituitary mass on CT or MRI when they are first diagnosed with PDH?
40-50%
What % of dogs will have a visible pituitary mass on CT or MRI when they are first diagnosed with PDH?
15-25%
Are there any commercially available diagnostic tests that can predict a PDH patient’s risk at developing neurological signs in dogs?
No.
The pro-opiomelanocortin/pro-ACTH levels are correlated to pituitary gland size in dogs with PDH but this is not commercially available
What’s the MOA of trilostane?
It’s a corticosteroid analog that inhibits 3-beta-hydroxysteroid –> essential for the production of cortisol and other steroids
What’s the MOA of pasireotide?
It’s a somatostatin receptor analog that has shown some efficacy in decreasing the pituitary tumour volume, improving ACTH concentration, urine creatinine:cortisol, and clinical signs
- AE: diabetes mellitus
- very expensive
What medications that can improve the “dopamine tone” has been used for canine PDH with some efficacy?
- selegiline
- cabergoline
What pituitary height to brain ratio would be considered to have a pituitary macroadenoma in dogs?
> 0.31
What’s the outcome of transsphenoidal hypophysectomy for dogs with pituitary tumours?
- periop survival = 91%
- MST = 781 days (~2y)
- median DFI = 951 days (~2.5y)
- Recurrence rate = 27%
- median time to recurrence = 555d (~1.5y)
- will need lifelong thyroid and glucocorticoid supplement, and desmopressin short term or long term
What’s the outcome reported in a prospective study in dogs with PDH treated with transsphenoidal hypophysectomy?
Success rate ~65%
- 12/150 (8%) died post-op
- 127/150 (85%) remission
- 32/150 (21%) recurrence
What are some surgical complications of transsphenoidal hypophysectomy in dogs?
- hemorrhage
- electrolyte imbalance
- neurological deficits
- decreased tear production
- thromboembolic disease
- recurrent PDH
- perioperative death
What’s the general outcome of RT for PDH in dogs?
- 2 to 3.8y
- smaller tumours had better outcome
- effective at controlling the neurological signs
- variable outcome for the Cushing’s aspect
What % of dogs/ cats will have HAC due to PDH?
80-85%
What’s the outcome of transsphenoidal hypophysectomy in cats with PDH?
-2/7 (29%) died within 4 weeks of surgery
- 2/7 (29%) died several months after the surgery
- 1/7 (14%) was in remission for 19 months
What are some surgical complications of transsphenoidal hypophysectomy in dogs?
- hypopituitarism (short or long term)
- electrolyte imbalance
- soft palate dehiscence
- reduced tear production
What’s the outcome of RT for feline PDH?
unclear how it manages the endocrine disease
What’s the medical treatment of choice for feline PDH?
trilostane
What’s the likelihood of acromegaly in cats?
- 10-15% of diabetic cats
- up to 30% of hard-to-control diabetic cats
What’s mechanism of insulin resistance in cats with acromegaly?
- due to GH-induced post-receptor defect in the action of insulin on target cells
- these cats keep on gaining weight! (opposite of a typical diabetic cats)
What’s the blood test that can be used to diagnose acromegaly?
- serum insulin-like growth factor 1 (IGF-1)
- sensitivity = 84%; specificity = 92%
- there can be some overlap with uncontrolled diabetic cats
Is serum IGF-1 concentration reflective of diabetic control for feline acromegaly treated with RT?
No, serum IGF-1 concentration doesn’t appear to correlate with improved diabetic control
What’s the outcome of surgery for acromegaly?
- only a few published cases
- 3/21 died post-op
- remaining 18 had reduction in IGF-1
- 14 achieved diabetic remission
What’s the outcome of SRT for feline acromegaly?
MST = 1072d (2.9y)
- no association noted between tumor size or serum IGF-1 concentration and survival
- 10 had acute RT side effects –> pred resolved issues
- 7/50 had hypothyroidism months to years post
- 39/41 reduced insulin dose
- 13/41 (32%) went into diabetic remission
What are some options for medical therapy for feline acromegaly?
- octreotide –> unsure of long term outcome
- pasireotide –> encouraging, but expensive and causes diarrhea