Oral + Mammary tumours

Question 1

What are clinical signs of oral tumours?

Answer 1

• Mass / facial swelling
• Oral bleeding
• Dysphagia / pain
• Halitosis
• Epistaxis
• Loose teeth / proliferative lesions noted at dentals (always biopsy)
• Cervical lymphadenopathy

Question 2

What are the most common oral tumours in dogs?

Answer 2

1. Malignant melanoma
2. Squamous cell carcinoma
3. Fibrosarcoma
4. (Acanthomatous ameloblastoma + peripheral odotogenic fibroma)

Question 3

How are oral tumours diagnosed / staged?

Answer 3

• Assessment under GA
• Dx = Biopsy (incisional wedge), FNA
• Staging = assessment of local LNs, thoracic imaging + abdominal imaging (for melanoma)

For all malignant tumours:
* FNA submandibular nodes
* Image retropharyngeal nodes and sample if possible
* If CT available consider lymphangiography

Question 4

How are primary oral tumours managed?

Answer 4

• Surgery - maxillectomy / mandibulectomy, (margins by histology) - cats may need feeding tube for months post-op
• For FSA, SCC surgery followed by adjuvant RT
• palliative RT alone when surgical excision impossible

Question 5

What are complications of oral surgery?

Answer 5

• Recurrence
• Dogs adapt well, cats = variable
• Bleeding
• Infection
• Altered cosmetic appearance
• Difficulty prehending food / messy eating
• Salivation
• Mandibular drift

Question 6

What is melanoma? What does it effect? Dx?

Answer 6

• Smaller old dogs = mean 11.4yrs, golden retriever, cocker spaniel, miniature poodle, chowchow
• Very locally invasive
• High metastatic rate
• Dx= melanin containing mesenchymal cells

Question 7

Tx of primary melanoma?

Answer 7

• Surgery - associated w high rates of local recurrence
• 35% 1yr survival
• Size significant for survival time
• Radiation therapy - usually 5 months till recurrence
• Anti-metastatic treatment = Plasmid vaccine immunotherapy - used in stage II + III, (20%) success, EXPENSIVE

Question 8

How are oral SCC treated?

Answer 8

• Low metastatic rate - local control = mainstay of therapy
• Surgery = mandible (10% recurrence), Maxilla (30%), MST 19-26months
• RT = MST 15 months
• Surgery + RT = MST 34months
• If other therapies impossible = medical = Piroxicam + carboplatin

Question 9

What is presentation of tonsillar SCC? Tx? Prognosis?

Answer 9

• Dysphagia, coughing
• Enlarged cervical lymph nodes = abcessation
• FNA yields necrotic debris and sometimes tumour cells
• Oral examination reveals enlargement of 1 or both tonsils
• Metastatic rate >70%
• Tx =
• Local control of tonsillar enlargement - surgery or RT
• Surgery or RT for lymph node metastasis
• Carboplatin or mitoxantrone chemotherapy might be beneficial
• Prognosis - MST 7 mths
  – Patients who receive the most therapy live longest
  – Control of local/regional disease most important

Question 10

What dogs are predisposed to fibrosarcomas? how invasive / metastatic are they

Answer 10

• Golden retrievers, Labradors
• Invasive
• Low / moderate metastatic risk

Question 11

What is Tx of fibrosarcomas?

Answer 11

• Local control mainstay of therapy but challenging
• Surgery single most important therapy =
• Margins 3-5cm+
• But recurrence rate is 40 – 60 %
• MST 1 yr after surgery
• Multimodal therapy often best =
• Surgery and RT - MST 18 – 26 months
• Recurrence rate ~ 30 %
• RT alone = MST – 7 months
• Smaller tumours = better outcomes
• T1 tumours – MST 31 months
• T2 and T3 tumours (> 2 cm) – MST 7 months

Question 12

What are epulides?

Answer 12

*Non-metastatic lesions arising from gingiva
* Acanthomatous ameloblastoma
* Aggressive local behaviour and bone invasion
* Peripheral ondotogenic fibroma
* Slow growing firm masses usually not invasive

Question 13

What is canine oral osteosarcoma?

Answer 13

• Not as rapidly metastatic as appendicular
  – many tumours metastasise
• Site and histological grade is prognostic
• Survival – mandibular > maxillary
• 14 – 18 mths vs 5 – 10 mths
• Complete excision vital: local recurrence >80%
• Most dogs with maxillary tumours die of recurrence
• Most dogs with mandibular tumours die of metastases

Question 14

What are uncommon oral tumour of the dog?

Answer 14

– MCT
– Haemangiosarcoma
* Extramedullary Oral Plasmacytoma - Stage to rule out multiple myeloma
* Oral lymphoma: a form of epitheliotrophic - Generally require multi-agent chemotherapy, Some dogs with oral (only) epitheliotrophic lymphoma can do well with RT alone
* Undifferentiated tumour of young dogs - Rare – grave prognosis

Question 15

What is the most common feline oral tumour? risk factors? signs?

Answer 15

SCC - locally invasive, low metastatic risk
* use of flea collars
* exposure to smoking
* canned food including canned tuna

• Can cause discomfort = anorexia

Question 16

Tx of SCC in cats + outcome?

Answer 16

• Outcome depends upon surgical options
  – Cats with surgically resectable disease can have a good outcome but recurrence is common
  – Best outcomes in rostral mandibular SCC
  – Soft tissue lesions affecting the tongue have a poor prognosis as resections are difficult
• Long term feeding tube often needed for several months
• RT occasionally helpful
• Electrochemotherapy is an emerging therapy

Question 17

What is feline fibrosarcoma? Tx?

Answer 17

• Usually middle aged or older
• Very locally invasive
• Main treatment is surgery – Good outcomes possible with
  mandibulectomy (Maxillectomy more difficult)

Question 18

What are other oral lesions to be aware of?

Answer 18

• Multilobular osteochondrosarcoma – dogs
  -Popcorn appearance - radiographically
• Viral papillomatosis - immunosuppressed dogs
  -Wart like lesions affecting oral soft tissues
• Eosinophilic granuloma - dogs (Husky and CKCS)
• Eosinophilic granuloma – cats
  -Typically erosive lesions affecting upper lip near midline
• Transmissible venereal tumour – dogs (vincristine!)
  -Proliferative lesion affecting dogs who have been licking

Question 19

What are risk factors for mammary tumours?

Answer 19

• Neutering =
• Neutering prior to first oestrus – 0.5 % life time risk
• Neutering prior to second oestrus – 8 % risk
• Neutering prior to third oestrus – 26 % risk
• No risk reduction if neutering after the second season
• Oestrogen / progestin use increase risk
• Obesity
• Age
• Breed- siamese, poodles, chiahuahua, dachshund, maltese

Question 20

What is approach to mammary tumours?

Answer 20

• Mammary mass
• > 70% have more than 1 tumour
• Examine other glands carefully
• About 50% of canine MG tumours are benign
• FNA can be useful to exclude other ddx
• e.g. mastitis, lipoma or mast cell tumour, hyperplasia
• Excisional biopsy by single or segmental mastectomy reasonable for single lesions without negative prognostic indicators
• E.g. small, non fixed lesions
• Staging prior to treatment of suspicious lesions

Question 21

What is pre-surgical assessment of canine mammary tumours?

Answer 21

• Clinical Examination =
• Tumours > 3 cm have poorer outcome
• Fixed tumours
• Palpably enlarged lymph nodes
• Local staging =
• Assessment of local lymph nodes
• Consider typical drainage patterns - Not absolute so assess all nodes
• Distant staging = Thoracic Xray, CT, US

Question 22

What is surgery of canine mammary tumours?

Answer 22

• Low risk - single mastectomy
• High risk / intact bitch – consider regional mastectomy
• Intact bitches =
• 55% develop a new tumour on the ipsilateral side hence consider unilateral chain mastectomy
• Likely hormone field effect therefore consider bilateral resection in young intact bitches with multiple tumours
• Excision margins
• For mobile lesions – whole gland removal enough
• Fixed lesions – need 2 cm margins and removal of affected abdominal fascia / wall

Question 23

What are post surgical prognostic factors?

Answer 23

• Tumour type =
• Benign versus malignant
• Less tissue heterogeneity associated with a poorer outcome (complex vs simple)
• Sarcoma especially osteosarcoma – poorer than carcinoma
• Possible prognostic factors
• Poor standardisation of data makes it difficult to determine the independent significance of tumour types
• Mitotic rate / Ki-67
• Grade
• Hormone receptor expression

Question 24

What is canine inflammatory carcinoma? Tx? Prognosis?

Answer 24

• Tumours extremely painful
• Easily mistaken for mastitis
• Generally all gland affected
• FNA yields inflammatory cells and tumour cells
• Excision not typically feasible - Recurrence very common
• Prognosis = Generally very poor
• Treatment is palliative
• Medical therapy might prolong survival – few months

Question 25

What is feline mammary tumours?

Answer 25

• Similar risk factors to dogs
• 85 – 95 % of feline mammary tumours are malignant
• Clinical presentation =
• > 60% have more than 1 tumour at diagnosis
• Hormone receptor expression frequencies are lower
• A significant differential is fibroepithelial hyperplasia - Usually all glands are enlarged

Question 26

What are prognostic factors of feline mammary tumours?

Answer 26

• Tumour size =
• > 2 cm – MST 6 months
• < 2 cm – MST > 3 years
• Lymph node metastasis =
• Lymphatic drainage less predictable than dog
• Assess inguinal and axillary nodes bilaterally
• Distant metastasis
• Breed - DSH have better outcome

Question 27

What is surgery of feline mammary tumours?

Answer 27

• Chain mastectomy preferred to single or regional mastectomy =
• Unilateral when lesions on one side
• Stage bilateral when lesions bilateral
• Surgical resection of inguinal and / or axillary lymph nodes for high risk tumours recommended

Question 28

Why would you perform ovariectomy in dogs at time of mammary tumour excision?

Answer 28

• Halves chance of new mammary tumour for benign mammary tumours

Answer 29

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