Oral Tumours Flashcards
How many cancers in dogs are oral?
6%
How many cancers in cats are oral?
3%
What are the most commonly encountered malignant tumours in dogs? (4)
malignant melanomas
squamous cell carcinomas
fibrosarcomas
osteosarcomas
In cats what are the most commonly encountered tumours? (2)
squamous cell carcinomas
fibrosarcomas
What clinical signs do Os usually report with oral tumours? (5)
- difficulty or reluctance to eat
- excessive drooling that may be blood tinged;
- strong smell from the mouth;
- lethargy;
- weight loss.
What are the most likely cancers to have positive chest radiographs at the time of diagnosis? (2)
Melanoma and squamous cell carcinoma of the caudal oral and pharyngeal area.
How much bone mineral is lost when lysis can be observed?
40%
Regional lymph nodes (mandibular and retropharyngeal) should be carefully
for enlargement or asymmetry. They should always be aspirated. When is this especially important?
Melanoma
Caudally situated squamous cell carcinoma.
What is the most prevalent oral tumour in dogs?
Malignant melanoma
Metastasis of malignant melanomas regular occur at an early stage; to where? (2)
Lymph nodes
Lungs
Oral malignant melanomas are thought to metastasise in what percentage of cases?
50-80%
How many malignant melanomas are amelanotic?
One third
What is the predilection site for oral melanomas?
Buccal mucosa
What size oral melanoma + have not metastasised to LN have a better pronogisis?
<2cm (stage I)
What size oral melanoma has a worse prognosis? (+ nodal metastatsis)
> 4cm
What is the most common oral tumour in cats?
SCC
SCC in dogs:
A) Aggressive nature?
B) Metastasis
A) Local aggressive
B) Rarely met
In dogs, what surgical technique is often needed for SCC. Why?
Resected en-bloc with the tumour (maxillectomy, mandibulectomy
- Underlying bone is often invaded
What SCC has a more aggressive behaviour?
Tonsils
What is a high-low” FSA?
In dogs, there often is a discrepancy between the grade of the tumour, as estimated by histopathology, and its clinical behaviour (Ciekot et al., 1994). Such tumours are known as “histologically low-grade but biologically high grade”
Where do oral fibrosarcomas have propensity for?
Palate
Where do fibrosarcomas invade? (2)
Bone and soft tissue
What type of treatment do canine oral fibromas and FSA?
AGGRESSIVE
Signalment for oral osteosarcoma:
A) Size dogs?
B) Age?
C) Sex?
A) Mid-large breed
B) middle- old
C) Female
Which of the following statements is correct?
A) Squamous cell carcinomas are the most common oral tumour in dogs.
B) Malignant melanomas are the most common oral tumour in dogs.
C) Squamous cell carcinomas are the most common oral tumour in cats.
D) Malignant melanomas are the most common oral tumour in cats.
B) Malignant melanomas are the most common oral tumour in dogs.
C) Squamous cell carcinomas are the most common oral tumour in cat
What is the most common odontoggenic tumour?
Ameloblastoma
What is seen radiographically with an ameloblastoma?
Osteolysis around tooth roots with cystic changes
Where do ameloblastoma metastasise?
Rarely do
Where does the acanthomatous ameloblastoma appear?
Gingiva and mucosa
Does underlying bone get infiltrated with acanthomatous ameloblastoma?
In most cases
What is the radiographic appearance of a acanthomatous ameloblastoma? (3)
infiltration, alveolar bone resorption, and tooth displacement.
What resection is needed for acanthomatous ameloblastoma? Why?
Wide or radical
Local recurrence is common
What were previously described fibromatous and ossifying epulides?
Peripheral Odontogenic Fibroma (POF)
Peripheral Odontogenic Fibroma (POF):
A) Growth rate?
B) Benign va malignant?
C) recurrence if adequately excised?
A) Slow
B) Benign
C) does not
What are Peripheral Odontogenic Fibroma (POF) characterised by?
The proliferation of fibrous tissue in which islands or strands of odontogenic epithelium are present.
Odontoma:
A) Benign vs malignant?
B) Cells? (2)
A) Benign
B) Epithieal + Mesenchymal
What is the radiographic appearance of an odontoma?
sharply defined mass of calcified material surrounded by a narrow radiolucent band or a variable number of tooth-like structures.
Where is Feline Inductive Odontogenic Tumour most commonly occuring?
Rostral maxilla
Does Feline Inductive Odontogenic Tumour metastasise?
No reports, but is locally invasive
What material can be found histologically with Peripheral odontogenic fibromas? (4)
Bone
Osteoid
Dentinoid
Cementum
What is the mainstay of treatment for most oral tumours?
Surgery
What contributes to risk of wound dehiscence with oral surgery? (4)
- Local conditions
- Limited connective tissue
- Movements
- Bacteria burden
What can be created to reduce oral tumour wound dehisence by increasing holding power of deeper tissue?
Bone tunnels
Why is a partial maxillectomy or mandibulectomy often needed for oral tumours?
Most malignant tumours and ameloblastomas invade bone,
What margins are required for excision of mandibular and maxillary malignant tumours:
A) Bone margins?
B) Soft tissue margins?
A) 2cm
B) 1cm
Most common intra-op complications of mandibulectomy and maxillectomy?
Blood loss
Hypotension
What contains the alveolar mandibular artery and vein?
Alveolar canal
How to reduce significant haemorrhage in a maxillectomy?
Performing the bone sections in a logical order with cutting the bone that contains a large vessel last
Post op mand/maxillectomy complications (6)
Incisional dehiscence
Epistaxis
Increased salivation
Ranula formation
Mandibular drift and malocclusion
Difficulty prehending food.
Who is a feeding tube recommended for post mand/maxillectomy?
cat
When is radiation therapy recommended? (3)
- Curative intent for small SCCC
- Localised tumour with incomplete margins
- Downstage tumour prior to Sx
What radiation therapy type is proposed for ameloblastoma?
Fractioned therapy
Radiotherapy prior to Sx has best results in which tumour type?
SCC
Why is systemic chemotherapy less important in oral tumours?
Death/PTS tends to be due to local dx not mets.
What chemo protocol can be used for a malignant melanoma? (3)
Cisplatin
Carboplatin
Malphalan
What are the response rate of malignant melanoma to chemo?
Less than 30%.
Which anatomical location of oral tumours are associated with a better prognosis?
Rostral
For an equivalent tumour type and grade, rostral tumours are associated with a better prognosis. why? (2)
- diagnosed earlier
- More amenable to complete excision
Which anatomical location of SCC are more likely to metastasis?
Caudal
Malignant Melanoma:
A) Mean survival, no Tx?
B) What tumour size has better prognosis?
C) With what have 6 to 19 months progression-free survival (PFS) times have been reported ?
A) 65 days
B) <2cm
C) Radiotherapy alone
Squamous Cell Carcinoma:
A) Dog 1 year survival?
B) Cat 1 year survival?
A) 57-91%
B) <10%
Is radiotherapy for Squamous Cell Carcinoma more sensitive in dogs or cats
dogs
What is the mean survival time with just surgery for a fibrosarcoma?
9-12 mo
Osterosarcoma:
A) 1 year survival rate after mandibulectomy
B) 1 year survival rate after maxillectomy?
A) 6-18mo
B) 4-10mo
True or false:
The prognosis is better for malignant melanomas of less than 2 centimetres in diameter.
True
True or false:
Dogs with squamous cell carcinomas are poorly responsive to radiation therapy.
False
True or false:
Cats with squamous cell carcinomas are more sensitive to radiotherapy than dogs.
False
True or false:
FSAs are widely regarded as poorly responsive to radiotherapy.
True
True or false:
Osteosarcoma Local recurrence is a major concern after surgery.
True
True or false:
The combination of surgery with radiotherapy or chemotherapy has been shown to significantly improve the outcome when oral osteosarcomas are incompletely excised.
False
