AGASACA + Perianal Tumors Flashcards
True or false - cats can develop perianal adenoma/perianal adenocarcinoma
False - don’t have perianal sebaceous glands
Development and progression of perianal adenomas is _____ with growth stimulated by ______ and suppressed by _____
Sex hormone-dependent androgens estrogens
Perianal adenomas in female dogs occur almost exclusively in ______
spayed animals - have low estrogen = no tumor suppression
T/F: Perianal adenocarcinomas are hormonally dependent?
False
Rate of metastasis for perianal adenocarcinomas
Low, <15%
Most frequent sites of mets from perianal adenocarcinomas? Less frequent?
Regional LN and lungs; liver, kidney, bone
What five things are increased histologically/molecularly in perianal adenocarcinomas compared to adenomas?
Increased proliferating cell nuclear antigen (PNCA), apoptotic corpuscles, Ki67, VEGF, serum magnesium levels
What is needed to definitively tell perianal adenoma from adenocarcinoma?
Incisional bx
What IHC can help differentiate perianal adenoma from adenocarcinoma?
Monoclonal Ab against carcinoma-associated Ags 4A9, 1A10; PCNA, Ki67
What can help differentiate a perianal adenocarcinoma from AGASACA?
cytokeratin expression patterns
What margins can perianal adenomas be removed with?
Minimal margins, <1cm
Other than surgical removal of the primary tumor, what else is recommended for treatment in dogs with perianal adenomas?
Castration
What if a perianal adenoma is diffuse or too large to be removed? Treatment?
Surgical staging - castration first, may shrink tumor Cryosurgery CO2 laser ablation Hyperthermia RT ECT
What is the repoarted response rate for perianal adenomas treated with ECT
>90%, 65% CR
Do perianal adenocarcinomas respond to castration?
Nope
What has a significant influence of DFI and OSTs for dogs with perianal adenocarcinoma?
Stage of tumor - T2 tumors (<5cm) do better
2-year control rate for T2 perianal adenocarcinoma treated with surgery? Also, what is a T2 tumor?
<5cm >60%
MST for dogs with LN or distant mets from perianal adenocarcinoma
7mo (but aggressive therapy not pursed for most dogs)
What breeds have an increased risk of AGASACA?
Spaniels (particularly English cocker spaniels) German Shepherds Alaskan malamutes Dachshunds
Gender/neuter status assoc. with risk of AGASACA?
Neutering may be associated with increased risk for males
What are the three histologic patterns of AGASACA?
Solid Tubules/Rosettes/Pseudorosettes Papillary
Which are the most common histologic patterns of AGASACA
solid and tubules/rosettes/pseeudorosettes in 95%
What is the rate of bilateral AGASACA (simultaneously or temporally separated)
up to 14%
Rate of paraneoplastic hypercalcemia in dogs with AGASACA?
16-53%
Mediator of hypercalcemia in canine AGASACA?
PTHrp from neoplastic tissue
Overall rate of mets for dogs with AGASACA? LN? Distant?
Overall: 26-96% LN 26-89% Distant 0-42%
What are the less common sites of AGASACA mets?
heart, omentum, stomach, adrenal glands, panc, kindeys, Ubladder, mediastinum
What has been associated histologically with risk of metastasis at diagnosis for canine AGASACA?
Marked peripheral infiltration into surrounding tissue, LV invasion, solid pattern
Does high or low levels of E-cadherin expression in AGASACA correlate with a better survival time?
Higher
Rate of mets from AG melanoma in dogs?
4/8 sublumbar LN, 1/11 pulmonary
Rate of mets from regional LN for feline AGASACA?
20%
Have bilateral AGASACA been reported in cats?
Nope
What percentage of dogs have an AGASACA be an incidental finding?
up to 47%
What is the most common clinical sign for cats with AGASACA?
Perineal ulceration or discharge
What IHC staining can confirm AGASACA dx if needed?
Cytokeratin pattern CK7+/CK14-
What was shown to be the only consistently abnormal feature of abdominal malignant LNs?
Size
What three LN centers can be involved in AGASACA
medial and internal iliac, sacral
What is the complication rate after local surgery for AGASACA and what is the most common complication?
5-24% wound dehisence, rectal perforation, rectocutaneous fistulation, incisional infection, transient fecal incontinence
What can help limit the complications of surgical removal of AGASACA
Smaller anoplasty - previous studies showed 40-60% rate of fecal incontinence when 120-270 degree anoplasties performed
Complication rate of LN extirpation for dogs with AGASACA?
0-12% - hemorrhage, uncresectable LN, LN rupture and abdominal wall dehisence
T/F: treatment of recurrent AGASACA or progressive nodal mets is not recommended for dogs as it does not improved survival
False
When can you pursue splenectomy for AGASACA?
If confirmed mets to spleen + context of slowly progressive dz and no other mets
What drugs have demonstrated antitumor activity in gross disease setting for AGASACA in dogs
carbo, cisplat, actinomycin D
Measurable response rates for dogs with AGASACA with bulky disease treated with RT (hypofx or fx protocols)?
38-75%
Over what radiation dose per fraction to the colon are late radiation side effects more likely to occur?
3Gy
Palliative RT protocols result in an improvement in clinical signs in up to ______, including resolution of____
up to 63% Obstipation
Palliative RT protocols can resolve ____% of hypercalcemic dogs with AGASACA. What improves this %?
RT alone 31% RT + Pred + bisphosphonate = 46% additional
Reported PFIs and MSTs for dogs treated with palliative RT for AGASACA?
PFI 10-11 mo MST 8-15mo
Is rate of local recurrence for dogs treated with AGASACA related to the completeness of excision?
Nope