Clinical Oncology Flashcards
List the 3 phases of multistage carcinogenesis
- Initiation
- Promotion/progression
- Metastasis
Define oncogene
Mutations in genes that result in a gain of function
Define tumor suppressor gene
Mutations in genes that result in a loss of function
List 3 types of oncogenes & their description
- Viral oncogene (retroviral sequences that cause mutations)
- Cellular oncogenes (cellular homologues of viral oncogenes)
- Proto-oncogenes (cellular oncogenes that do not have mutating potential in their native state until altered)
List 4 mechanisms of oncogene activation
- Chromosomal translocation
- Gene amplification
- Point mutations
- Viral insertions
Oncogenes are __, whereas tumor suppressor genes are __
Think about genetic inheiritence
Oncogenes are dominant (only one allele needs to be affected)
Tumor suppressor genes are recessive (both alleles need to be affected)
List the 7 acquired capabilities of a cancer cell
- Self sufficient growth
- Insensitivity to anti-growth signals
- Evasion of apoptosis
- Limitless replicative potential
- Sustain angiogenesis
- Invade & metastisise
- Evasion of the host immune system
AM I SARI
How do you describe a tumor using the TNM staging system
I.e., what do the letters stand for?
T - size & invasiveness of tumor
N - status of nodual metastasis
M - status of distant metastasis
Which tumors would you NOT use the TNM staging system for?
Brain or spinal cord tumors, lymphoma or leukaemia
What is the incidence of cancer in dogs?
1 in 3-4
What is the incidence of cancer in cats?
1 in 5-6
List 3 treatment modalities for cancer
- Surgery
- Chemotherapy
- Radiotherapy
Define the stage of a tumor
How is this different from grade?
The clinical extent of disease
Grade is the pathological description of the tumor
What are you looking for on a physical exam of a solitary tumor or lymph nodes?
List 3-5 things
Size, mobility, ulceration, texture/consistency, & relationship with neighbouring structures
Which tumors is contrast radiography best at identifying?
GI or CNS tumors
Which tumors is CT best at identifying?
Bony or pulmonary lesions
Which tumors is ultrasound best for identifying
Tumors on internal lymph nodes
List 4 things biopsy’s are good at identifying
- The presence of neoplastic disease
- Tumor type
- Tumor grade
- The adequacy of surgical exicsion
List 4 advantages of cytology
- Easily recovered
- Collected with little disruption
- Multiple sites can be sampled
- Preparations can be rapidly mounted and stained
What type of tumors should you use a skin punch biopsy for?
Skin & superficial soft tumors
Which tumors should you use a needle biopsy for?
Solid tumors from internal organs or bone
What is an incisional biopsy, and when would you use it?
It is the surgical removal of a solid piece of tissue
Where a substaintial amount of tissue is required for histopathology, the lesion is too large to easily excise, or treatment will be based on the results
Not usually worth it, but it depends
What is an exicisonal biopsy, and when would you use it?
It is the complete surgical removal of a tumor
Should be used when pre-treatment histopathology does not change the treatment (ex. mammary carcinoma)
For which conditions would you take a bone marrow biopsy?
Provide 3 examples
Conditions affecting the lymphoid & myeloid systems
1. Non-regenerative anaemia
2. Secondary immune mediated hemolytic anaemia
3. Haematopoietic tumors
List 1 advantage and disadvantage of needle biopsy’s
Adv: Inaccessbile sites can be accessed without surgery
Disadv: Can have a greater incidence of complications compared to FNAs
List 1 advantage and disadvantage of incisional biopsy’s
Adv: exposes tumor site to allow accurate selection of sample
Disadv: requires general anaesthesia
List 5 tumors of round cells
Think about each round cell (there’s 5)
- Lymphoma
- TVT tumor
- Mast cell
- Plasmacytoma
- Histiocytic tumor
Which system is MRI best used for evaluating?
The CNS
Define a dirty margin
The tumor is touching the cut edge of the sample
Define a clean margin
Normal tissues are touching the cut edge of the sample
Define a paraneoplastic syndrome
One or more clinical signs induced by a tumor distant from its primary site
List 2 ways in which PNS’s can arise
Think about what the tumor does
- Through secreted factors (hormones, cytokines, enzymes etc.)
- By dysregulation of the immune system
Define a orthotopic/topic PNS
Provide an example
PNS arising from the functional tumors of endocrine tissue (i.e., there is excess hormone production)
Tumors of pancreatic islet cells cause hypoglycaemia
Define an ectopic PNS
Provide an example
PNS arising from non-endocrine tumors that produce active factors which mimic the effects of hormones
Large hepatic tumors cause hypoglycaemia
In which species is paraneoplastic hypercalcaemia more common?
Dogs
Rare in cats
Which disease is most commonly associated with paraneoplastic hypercalaemia?
Lymphoma (mostly T cell tumours)
List 3 clinical signs of hypercalaemia
- PU/PD (and associated hypovoluaemia)
- Neuromuscular weakness
- CNS depression
List 5 differential diagnosis’s for hypercalcaemia
- Primary hyperparathyroidism
- Primary renal disease
- Hypervitaminosis D
- Hypoadrenocorticism
- Malignancy (most common)
Which 2 hormones should you look at when diagnosing hypercalcaemia, and how will they be changed in neoplastic disease?
PTH and PTHrP
PTH will be decreased and PTHrP will be increased in neoplastic disease
Why should you avoid furosemide as a treatment option for hypercalcaemia?
It may worsen hypovoluaemia and azotemia (nitrogen in the blood)
Which treatment option for hypercalcaemia should only be used short term?
Calcitonin
How do bisphosphonates work to treat hypercalcaemia?
They mimic pyrophosphates, which regulate the precipitation and removal of minerals from bone
List 3 clinical signs of hypoglycaemia
- Nervous system dysfunction
- Tachycardia
- Dilated pupils
List 5 differential diagnosis’s for hypoglycaemia
- Age/breed factors
- Sepsis
- Liver failure
- Insulinoma
- Drug side effects
List 3 treatment options for hypoglycaemia
- Revmoval of tumor
- Frequent small meals + glucocorticoid therapy
- Pre-surgical IV dextrose (severe cases)
What are the 2 forms of paraneoplastic hypoglycaemia, and what causes them?
- Topic hypoglycaemia (insulinoma is most common cause)
- Ectopic hypoglycaemia (large hepatic tumors or haemangiosarcomas)
Define cancer cachexia
Weight loss despite adequate caloric intake
List 2 causes for neoplastic hyperviscosity
- Increased plasma proteins (B cell tumors)
- Increased cell number (renal tumors)
List 3 clinical signs of neoplastic hyperviscosity
- PU/PD
- CNS depression
- Ocular changes
Describe the pathophysiology of neoplastic hyperhistaminaemia
Tumors of mast cells cause mast cell degranulation and histamine release, histamine stimulates H2 (and H1) receptors, which increases gastrin production causing hyperacidity, hypermobility and ulceration
H1 receptor activation causes vasodilation (increasing permeability) and hypotension (flushing)
Which disease is neoplastic myasthenia gravis associated with?
Thyomas
Also immune mediated diseases
In which species do we most commonly see cutaneous paraneoplastic syndromes?
How does it present?
Cats
Presents as alopecia or exfoliative dermatitis
List 4 tumors with which you will see peripheral neuropathies
- Insulinoma
- Carcinoma
- Sarcoma
- Melanoma
