Carcinomas
Wendy Blount, DVM
Carcinomas
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Squamous cell carcinoma (canine & feline)
Transitional cell carcinoma (canine)
Mammary Gland Tumor (canine & feline)
Perianal tumor (canine)
Anal sac tumors (canine)
Thyroid Carcinoma
• Meningioma
Squamous Cell Carcinoma
Feline Squamous Cell carcinoma
• Second most common tumor in the cat
• Oral SCC behaves differently than skin SCC
Canine Squamous Cell Carcinoma
• Similar behavior as SCC in cats, but not as
common
Squamous Cell Carcinoma
Feline Cutaneous Squamous Cell Carcinoma
• Most frequently on the head
– Pinnae, nose, eyelids
• Caused by sun exposure to light colored skin
• Progression over time
– Solar dermatitis – crusts and scabs
– Actinic dermatitis - plaques
– SCC in situ – noninvasive mass
– Invasive SCC – ulcerative, invasive mass
Squamous Cell Carcinoma
Feline Cutaneous Squamous Cell Carcinoma
Solar dermatitis
Actinic dermatitis
Squamous Cell Carcinoma
Feline Cutaneous Squamous Cell Carcinoma
SCC in situ
SCC
Squamous Cell Carcinoma
Feline Cutaneous Squamous Cell Carcinoma
• Cytology often not helpful
– Very inflammatory
• Dx - histopathology
• Staging not usually necessary, as metastasis is
rare
• Tx – early lesions
– Surgery, cryosurgery, Strontium radiotherapy,
photodynamic therapy
– immunomodulatory agent imiquimod (AldaraTM) as a
topical cream
Squamous Cell Carcinoma
Feline Cutaneous Squamous Cell Carcinoma
• Tx – advanced lesions
– Difficult to treat
– Removal of the nasal planum is possible, but
disfiguring
Squamous Cell Carcinoma
Feline Cutaneous Squamous Cell Carcinoma
Partial planectomy
Pinnectomy and
planectomy
Squamous Cell Carcinoma
Feline Cutaneous Squamous Cell Carcinoma
Untreated for too long
Squamous Cell Carcinoma
Feline Oral Squamous Cell Carcinoma
• Most common oral tumor in the cat
• Gingiva, tongue/sublingual, tonsil
• Much more aggressive than cutaneous SCC
• Maxillary tumors can mimic tooth abscess
• Surgery often not possible
• Radiation sensitive, but high morbidity –
mandatory feeding tube
Squamous Cell Carcinoma
Feline Oral Squamous Cell Carcinoma
• Chemotherapy not effective
• NSAIDs are palliative
• Median survival 44 days + NSAIDs
• 9% survival at one year
• Survival more than a few months even with
multimodal therapy is rare (BJ Honeycat)
Squamous Cell Carcinoma
Feline Lung Squamous Cell Carcinoma
• Often presents as multiple nail bed tumors
• Primary tumor is found on chest x-rays
• Always take chest x-rays prior to amputating a
possibly neoplastic nail bed in a cat
• Animals with systemic neoplasia often do not
do well under anesthesia
• Amputation is palliative only
Squamous Cell Carcinoma
Canine Digital Squamous Cell Carcinoma
• Nail bed SCC can be primary in the dog
• MSA, MCT and SCC are most common digital
tumors in the dog
• SCC more likely to show bony lysis than others
• Toe amputation is often curative
• LN aspiration and thoracic radiographs
indicated prior to surgery
Transitional Cell Carcinoma
• Most common bladder tumor in the dog (90%)
• Most common symptoms are hematuria and
stranguria
• Things that increase suspicion
– Atypical transitional cells in the urine sediment
– Mass in the bladder or urethra on imaging
– Thickened urethra on rectal exam (sheltie)
– Ruptured urethra on catheterization (chihuahua)
Transitional Cell Carcinoma
Etiology
• Exposure to older topical flea treatments, dips
and lawn chemicals (28x)
• Possibly cyclophosphamide therapy
• Neutered > sexually intact (2.5x)
• Scottish terriers 18-20x other dog breeds
– Eating vegetables 3x a week is protective
• Shelties, Westies, beagles 3-5x other breeds
Transitional Cell Carcinoma
Dx – histopath
• Surgery, cystoscopy, traumatic bladder wash
• Percutaneous aspiration can seed tumor cells
and should be avoided
• Take care to avoid seeding during surgery
Transitional Cell Carcinoma
Tx
• At one time, radiation therapy was recommended,
as TCC is highly responsive
– But resulting permanent incontinence was common
• If at the apex, resection can produce long disease
free interval (1-2 years) – (Tess)
• Secondary UTI is common – treat PRN
• Ureteral stents can restore urine flow
• Urethral stents can relieve obstruction if urethral
sphincter and continence can be preserved
• Prepubic cystostomy tube can relieve obstruction
Transitional Cell Carcinoma
Tx - NSAIDs
• Mainstay of treatment is medical therapy
• Not curative, but remission is achieved in 15-20%
and stable disease is reached in 75% of dogs
• Piroxicam only – median survival 195 days
– 0.3 mg/kg PO SID to QOD
• Deramaxx only - median survival 323 days
– 3 mg/kg PO SID
• Previcox similar success
• Median survival surgery only is 109 days
Transitional Cell Carcinoma
Tx - Chemo
• Mitoxantrone and piroxicam (see chemo
section for details)
– 35% remission with minimal toxicity
– Median survival 291-350 days
• Single agent vinblastine (see MCT notes)
– 36% remission
– 50% stable disease
– Most of these had failed other therapies
– Relatively more toxicity than mitoxantrone +
piroxicam
Transitional Cell Carcinoma
Tx - Chemo
• Doxorubicin and cyclophosphamide
– Median survival 259 days
• Metronomic therapy
– Chlorambucil 4 mg/m2 PO SID
– See Chemotherapy section for monitoring
– 29 of 31 dogs had failed prior TCC treatment
– 3% partial remission, 67% stable disease, 30%
progressive disease
– Median survival 221 days
Transitional Cell Carcinoma
Px
• Euthanasia often due to obstruction,
metastasis or both
• 50% have metastasis at the time of death
• Some will invade the sublumbar lymph nodes
and then the spinal cord and present as acute
posterior paralysis, often with urethral
obstruction (1 cat, 2 Rottweilers)
Transitional Cell Carcinoma
Canine Mammary Gland Tumor
• 42% of tumors in all intact female dogs
• Rare in dogs less than 5 years old
• duration of exposure to ovarian hormones early in life
determines the overall mammary cancer risk (Dorn et
al, 1968).
– 0.5% if OHE prior to the first heat
– 8 if OHE prior to the 2nd heat
– 26% if OHE after the 2nd heat
• tumor risk increases incrementally each year and
plateaus around 11–13 (Schneider, 1970)
• intact females are more likely to have an anaplastic
tumor type, compared to dogs spayed early or late in
life, prior to MGT (Ogilvie, 2006)
Canine Mammary Gland Tumor
The effect of neutering on the risk of mammary
tumours in dogs--a systematic review. J Small
Anim Pract. June 2012;53(6):314-22. W
Beauvais1; J M Cardwell; D C Brodbelt
Due to the limited evidence available and the
risk of bias in the published results, the
evidence that neutering reduces the risk of
mammary neoplasia, and the evidence that
age at neutering has an effect, are judged to
be weak and are not a sound basis for firm
recommendations.
Canine Mammary Gland Tumor
• Review article – not a clinical study at all
• Conclusions:
– 9/13 were judged to have a high risk of bias, and
though they all showed a connection between MGT
and failure to spay, they were not considered as
evidence.
– The remaining four were classified as having a
moderate risk of bias.
• One study found an association between neutering and a
reduced risk of mammary tumors.
• Two studies found no evidence of an association.
• One reported to have "some protective effect" of neutering
on the risk of mammary tumors.
Canine Mammary Gland Tumor
BMJ. 2003 Dec 20;327(7429):1459-61. Parachute use to prevent death
and major trauma related to gravitational challenge: systematic
review of randomised controlled trials. Smith GC1, Pell JP.
OBJECTIVES: To determine whether parachutes are effective in
preventing major trauma related to gravitational challenge.
DESIGN: Systematic review of randomised controlled trials.
RESULTS: We were unable to identify any randomised controlled trials
of parachute intervention.
CONCLUSIONS: As with many interventions intended to prevent ill
health, the effectiveness of parachutes has not been subjected to
rigorous evaluation by using randomised controlled trials. Advocates
of evidence based medicine have criticised the adoption of
interventions evaluated by using only observational data.
We think that everyone might benefit if the most radical protagonists
of evidence based medicine organised and participated in a double
blind, randomised, placebo controlled, crossover trial of
the parachute.
Canine Mammary Gland Tumor
• 70% have more than one tumor at the time of
diagnosis
• Mammary gland tumors can be epithelial,
myoepithelial, mesenchymal or mixed
• Complex MGT – epithelial and myoepithelial
• Mixed MGT – epithelial and mesenchymal
Canine Mammary Gland Tumor
MGT Stages
• Stage I – less than <3cm and localized
• Stage II – 3-5 cm and localized
• Stage III - >5cm and localized
• Stage IV – any size, metastasis to lymph node
• Stage V – any size, distant metastasis
Canine Mammary Gland Tumor
MGT Staging
• CBC – check for evidence of infection
• Profile – hypercalcemia
• Aspirate draining lymph node
• Thoracic radiographs – 3 views
• Abdominal US
Canine Mammary Gland Tumor
MGT Staging
• CBC – check for evidence of infection
• Profile – hypercalcemia
• Aspirate draining lymph node
• Thoracic radiographs – 3 views
• Abdominal US
Canine Mammary Gland Tumor
Surgery
• As with all masses removed, label margins so
they can be read out
– Describe the location of the lesion
– Mark one end of one direction (e.g., cranial or
caudal) with one type suture
– Mark one end of the plane 90O to above with
another type suture, if necessary
– Don’t forget to describe your labeling on the
submission form
Canine Mammary Gland Tumor
Surgery – OHE?
• The majority of MGT of epithelial origin express
estrogen receptors, suggesting that reproductive
hormones may play a role in the pathogenesis
• 755 days median survival - dogs spayed at or
within 2 years before MGT surgery
• 286 days median survival – dogs not spayed at
MGT surgery
• 301 days median survival – dogs spayed more
than 2 years prior to MGT surgery
• It’s rare for MGT to develop more than 2 years
after OHE
Canine Mammary Gland Tumor
Prognosis
• 50-60% of mammary gland tumors are benign
• 98% of tumors <1 cm are benign
• 50% of tumors >3cm are malignant
• Malignant tumors develop from benign
masses
• Early removal is usually curative
Canine Mammary Gland Tumor
Inflammatory Mammary Carcinoma
• Acute onset of painful, extensive swelling of
the mammary glands
• Fine needle aspiration with a 25g needle can
drip blood for days (DIC)
• Rapidly progressive
• Grave prognosis
Perianal Tumors
• “aka” hepatoid tumor
• Most common in older intact male dogs
– And females with testosterone producing adrenal
tumors
• Tumor site – perineum > tail, abdomen
• Most often found without symptoms
• Tenesmus can be caused by the lesion or
submandibular lymphadenopathy (palpable
rectally)
• 60-80% benign
• Those that are malignant often behave as anal
sac tumors
Perianal Tumors
• Staging prior to surgery
– Abdominal rads and/or sonography to evaluate
sublumbar lymph nodes
• Large tumors >2cm and single tumors should be
removed
• If multiple small tumors or coalescing tumors,
castrate first (if male)
– Remove any tumors that do not resolve in 2-4 weeks
• Unless males are castrated, new tumors will likely
arise
Anal Sac Carcinoma
• Highly malignant
– Locally invasive AND distant metastases
• 90% develop hypercalcemia
– 25-50% are hypercalcemic at diagnosis
• 50-94% have lymph node metastasis at the
time of diagnosis
Anal Sac Carcinoma
Presentation
• Found on anal sac expression
• Dyschezia, tenesmus, ribbon-like stools
• Attention to the perineum, scooting
• Perianal bleeding
• PU-PD (hypercalcemia)
• Hind limb weakness or posterior paralysis
• May be bilateral – check the other side
Anal Sac Carcinoma
Staging
• Profile – hypercalcemia, azotemia
• Abdominal rads and/or sonography
– Sonography more sensitive than rectal palpation
or rads for finding enlarged sublumbar LN
• Thoracic radiographs – 3 views
• Aspirate popliteal and inguinal lymph nodes
– Sublumbar if large enough and you are
comfortable doing this with ultrasound guidance
Anal Sac Carcinoma
Median Survival – no treatment
• 7-9 months
– masses larger than 3cm
– Dogs with hypercalcemia and/or pulmonary
metastasis
• 18-19 months
– Masses smaller than 3cm
– Dogs with normocalcemia and no lung mets
Anal Sac Carcinoma
Median Survival
• Surgery only
– 90% survival at 6 months (hypercalcemia often goes
into remission, even if incomplete excision)
– 65% survival at one year
– 29% survival at 2 years
– 20% temporary fecal incontinence, some permanent
– Wound infection and sepsis can occur
– 30% perioperative fatality when sublumbar lymph
nodes are removed
Anal Sac Carcinoma
Median Survival
• Multi-modal therapy – surgery, radiation of
nodes, doxorubicin/carboplatin
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18-26 months median survival
86% survival at 6 months (similar to surgery alone)
69% survival at one year (same as surgery alone)
36% survival at 2 years (maybe more than surgery
alone – 29%)
– 14% survival at 3 years
• Median survival 22 months with radiation alone
– 15% rectal structure
Thyroid Carcinoma - Dog
• 3-4% of tumors in dogs
• 90% are malignant
• Boxers, Golden Retrievers and Beagles are at
increased risk
• Most common presentation is ventral cervical
mass
– Change in bark or breathing
– Cough
– Occasionally swelling or regurgitation
• Hyperthyroidism is rare
Thyroid Carcinoma - Dog
Diagnosis
• Cytology
– Vascular – may get blood only
– often confirm endocrine origin, but it can be
difficult to confirm malignancy
– US guidance can target a solid spot for better
results
• Incisional biopsy can result in massive
hemorrhage – not recommended
• US can confirm mass is of thyroid origin
Thyroid Carcinoma - Dog
Staging
• Ultrasound – assess lymph nodes and local
invasion
• 3 view thorax
Thyroid Carcinoma - Dog
Treatment
• Surgery
– If freely moveable, surgery can result in a long
disease free interval
– If invasive, surgery can be difficult
• Hemorrhage
• Damage to recurrent laryngeal nerves (LP) or carotid
aa.
• Hypocalcemia if all parathyroids damaged or removed
Thyroid Carcinoma - Dog
Treatment
• External Beam Radiation
– For unresectable masses
• 80% stable disease at 1 year, 72% at 3 years
– For residual disease after surgery
• Chemotherapy
– Single agent carboplatin or mitoxantrone
– Or alternate
– Every 3 weeks, 4-6 treatments
– Outcome is unknown
Thyroid Carcinoma - Cat
• Most present with hyperthyroidism
• Diagnosis made by thyroid nuclear scan
– Or histopath after thyroidectomy
– Cytology may be diagnostic
• Treatment
– Higher dose of I131 – may need to be repeated
– Surgery if no evidence of metastasis on nuclear
scan
• Chemotherapy remains unexplored
Meningioma
• Most common brain tumor in geriatric dogs
and cats
• Dolichocephalic breeds predisposed
• 10% of non-lymphoma neoplasias in cats are
meningiomas
• Multiple meningiomas are not uncommon in
cats
• Despite being “not malignant,” usually
eventually result in death if not removed
Meningioma
Clinical Signs
• Subtle changes in behavior over time
– Patients adapts to gradual increase in intracranial
pressure
• Acute onset of severe neurologic signs not
unusual – Cerebral signs most common
– Cluster seizures, changes in behavior
– Contralateral blindness, ipsilateral circling, looking
to that side, pacing
– Stupor, head pressing, getting stuck in corners
– CP deficits worse in the rear, UMN ataxia
Meningioma
Clinical Signs
• Cranial nerve signs if in the brain stem
• Spinal reflex deficits if in the spinal cord
– LMN 2 dermatomes caudal to the lesion
– UMN below the lesion
• Remember cats can have more than one
Meningioma
Diagnosis
• Radiographs are rarely helpful
– Occasionally the tumor is mineralized
• CSF tap rules out infectious and inflammatory
diseases
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Increased CSF pressure can result in herniation
Hyperventilate with 10 breaths prior to stick
Give mannitol if high CSF pressure is suspected
Pacing, altered consciousness, dysphoria
Increased protein, increased mononuclear cells
Unusal to see neoplastic cells on sediment
Meningioma
Diagnosis
• MRI gives more information than CT
• Contrast may be required
• Isolated meningeal tumors presumed to be
meningiomas until histopath says otherwise
• Biopsy prior to surgery not generally
recommended
Meningioma
Treatment
• Surgery often curative
– But expensive
– Frontal lobe tumors do well
– Brain stem surgeries carry high morbidity
• Radiation without surgery can give long term
palliation
• Palliative Medications
– Glucocorticoids
– anticonvulsants
Carcinomas
Client Handouts
• Squamous Cell Carcinoma
• Transitional Cell Carcinoma
• Mammary Gland Tumor – Canine
• Mammary Gland Tumor – Feline
• Thyroid Carcinoma
• Meningioma
Acknowledgements
• Jane M. Dobson, MA, BVetMed, DVetMed, DECVIMCA&Onc, MRCVS
Department of Veterinary Medicine, University of
Cambridge, Cambridge, UK
• Deborah W. Knapp, DVM, DACVIM (Oncology)
Purdue University, West Lafayette, IN, USA
• Karin Ulrikke Sorenmo, DVM, DACVIM, DECVIM-CA
(Oncology)
Veterinary Hospital of the University of Pennsylvania
Philadelphia, PA, USA
Acknowledgements
• Erik Teske, DVM, PhD, Dip ECVIM-CA
Clinical Sciences, Companion Animals
Utrecht University, THE NETHERLANDS
• Katherine Skorupski, DVM, DACVIM (Oncology)
Assistant Professor of Clinical Medical Oncology
University of California, Davis
• Greg Ogilvie, DVM, DACVIM (Oncology)
Director, Angel Care Cancer Center, California
Acknowledgements
• Laura Blackwood, BVMS (Hons), PhD, MVM,
CertVR, DECVIM-CA (Oncology), MRCVS, RCVS
Small Animal Teaching Hospital, University of
Liverpool, Leahurst, Neston, UK
• Richard A. LeCouteur, BVSc, PhD, Diplomate
ACVIM (Neurology), DECVN
University of California
Davis, California, USA