Clinical Oncology

Question 1

List the 3 phases of multistage carcinogenesis

Answer 1

1. Initiation
2. Promotion/progression
3. Metastasis

Question 2

Define oncogene

Answer 2

Mutations in genes that result in a gain of function

Question 3

Define tumor suppressor gene

Answer 3

Mutations in genes that result in a loss of function

Question 4

List 3 types of oncogenes & their description

Answer 4

1. Viral oncogene (retroviral sequences that cause mutations)
2. Cellular oncogenes (cellular homologues of viral oncogenes)
3. Proto-oncogenes (cellular oncogenes that do not have mutating potential in their native state until altered)

Question 5

List 4 mechanisms of oncogene activation

Answer 5

1. Chromosomal translocation
2. Gene amplification
3. Point mutations
4. Viral insertions

Question 6

Oncogenes are __, whereas tumor suppressor genes are __

Think about genetic inheiritence

Answer 6

Oncogenes are dominant (only one allele needs to be affected)
Tumor suppressor genes are recessive (both alleles need to be affected)

Question 7

List the 7 acquired capabilities of a cancer cell

Answer 7

1. Self sufficient growth
2. Insensitivity to anti-growth signals
3. Evasion of apoptosis
4. Limitless replicative potential
5. Sustain angiogenesis
6. Invade & metastisise
7. Evasion of the host immune system

AM I SARI

Question 8

How do you describe a tumor using the TNM staging system

I.e., what do the letters stand for?

Answer 8

T - size & invasiveness of tumor
N - status of nodual metastasis
M - status of distant metastasis

Question 9

Which tumors would you NOT use the TNM staging system for?

Answer 9

Brain or spinal cord tumors, lymphoma or leukaemia

Question 10

What is the incidence of cancer in dogs?

Answer 10

1 in 3-4

Question 11

What is the incidence of cancer in cats?

Answer 11

1 in 5-6

Question 12

List 3 treatment modalities for cancer

Answer 12

1. Surgery
2. Chemotherapy
3. Radiotherapy

Question 13

Define the stage of a tumor

How is this different from grade?

Answer 13

The clinical extent of disease

Grade is the pathological description of the tumor

Question 14

What are you looking for on a physical exam of a solitary tumor or lymph nodes?

List 3-5 things

Answer 14

Size, mobility, ulceration, texture/consistency, & relationship with neighbouring structures

Question 15

Which tumors is contrast radiography best at identifying?

Answer 15

GI or CNS tumors

Question 16

Which tumors is CT best at identifying?

Answer 16

Bony or pulmonary lesions

Question 17

Which tumors is ultrasound best for identifying

Answer 17

Tumors on internal lymph nodes

Question 18

List 4 things biopsy’s are good at identifying

Answer 18

1. The presence of neoplastic disease
2. Tumor type
3. Tumor grade
4. The adequacy of surgical exicsion

Question 19

List 4 advantages of cytology

Answer 19

1. Easily recovered
2. Collected with little disruption
3. Multiple sites can be sampled
4. Preparations can be rapidly mounted and stained

Question 20

What type of tumors should you use a skin punch biopsy for?

Answer 20

Skin & superficial soft tumors

Question 21

Which tumors should you use a needle biopsy for?

Answer 21

Solid tumors from internal organs or bone

Question 22

What is an incisional biopsy, and when would you use it?

Answer 22

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

Question 23

What is an exicisonal biopsy, and when would you use it?

Answer 23

It is the complete surgical removal of a tumor
Should be used when pre-treatment histopathology does not change the treatment (ex. mammary carcinoma)

Question 24

For which conditions would you take a bone marrow biopsy?

Provide 3 examples

Answer 24

Conditions affecting the lymphoid & myeloid systems
1. Non-regenerative anaemia
2. Secondary immune mediated hemolytic anaemia
3. Haematopoietic tumors

Question 25

List 1 advantage and disadvantage of needle biopsy's

Answer 25

Adv: Inaccessbile sites can be accessed without surgery Disadv: Can have a greater incidence of complications compared to FNAs

Question 26

List 1 advantage and disadvantage of incisional biopsy's

Answer 26

Adv: exposes tumor site to allow accurate selection of sample Disadv: requires general anaesthesia

Question 27

List 5 tumors of round cells | Think about each round cell (there's 5)

Answer 27

1. Lymphoma 2. TVT tumor 3. Mast cell 4. Plasmacytoma 5. Histiocytic tumor

Question 28

Which system is MRI best used for evaluating?

Answer 28

The CNS

Question 29

Define a dirty margin

Answer 29

The tumor is touching the cut edge of the sample

Question 30

Define a clean margin

Answer 30

Normal tissues are touching the cut edge of the sample

Question 31

Define a paraneoplastic syndrome

Answer 31

One or more clinical signs induced by a tumor distant from its primary site

Question 32

List 2 ways in which PNS's can arise | Think about what the tumor does

Answer 32

1. Through secreted factors (hormones, cytokines, enzymes etc.) 2. By dysregulation of the immune system

Question 33

Define a orthotopic/topic PNS | Provide an example

Answer 33

PNS arising from the functional tumors of endocrine tissue (i.e., there is excess hormone production) | Tumors of pancreatic islet cells cause hypoglycaemia

Question 34

Define an ectopic PNS | Provide an example

Answer 34

PNS arising from non-endocrine tumors that produce active factors which mimic the effects of hormones | Large hepatic tumors cause hypoglycaemia

Question 35

In which species is paraneoplastic hypercalcaemia more common?

Answer 35

Dogs | Rare in cats

Question 36

Which disease is most commonly associated with paraneoplastic hypercalaemia?

Answer 36

Lymphoma (mostly T cell tumours)

Question 37

List 3 clinical signs of hypercalaemia

Answer 37

1. PU/PD (and associated hypovoluaemia) 2. Neuromuscular weakness 3. CNS depression

Question 38

List 5 differential diagnosis's for hypercalcaemia

Answer 38

1. Primary hyperparathyroidism 2. Primary renal disease 3. Hypervitaminosis D 4. Hypoadrenocorticism 5. Malignancy (most common)

Question 39

Which 2 hormones should you look at when diagnosing hypercalcaemia, and how will they be changed in neoplastic disease?

Answer 39

PTH and PTHrP PTH will be decreased and PTHrP will be increased in neoplastic disease

Question 40

Why should you avoid furosemide as a treatment option for hypercalcaemia?

Answer 40

It may worsen hypovoluaemia and azotemia (nitrogen in the blood)

Question 41

Which treatment option for hypercalcaemia should only be used short term?

Answer 41

Calcitonin

Question 42

How do bisphosphonates work to treat hypercalcaemia?

Answer 42

They mimic pyrophosphates, which regulate the precipitation and removal of minerals from bone

Question 43

List 3 clinical signs of hypoglycaemia

Answer 43

1. Nervous system dysfunction 2. Tachycardia 3. Dilated pupils

Question 44

List 5 differential diagnosis's for hypoglycaemia

Answer 44

1. Age/breed factors 2. Sepsis 3. Liver failure 4. Insulinoma 5. Drug side effects

Question 45

List 3 treatment options for hypoglycaemia

Answer 45

1. Revmoval of tumor 2. Frequent small meals + glucocorticoid therapy 3. Pre-surgical IV dextrose (severe cases)

Question 46

What are the 2 forms of paraneoplastic hypoglycaemia, and what causes them?

Answer 46

1. Topic hypoglycaemia (insulinoma is most common cause) 2. Ectopic hypoglycaemia (large hepatic tumors or haemangiosarcomas)

Question 47

Define cancer cachexia

Answer 47

Weight loss despite adequate caloric intake

Question 48

List 2 causes for neoplastic hyperviscosity

Answer 48

1. Increased plasma proteins (B cell tumors) 2. Increased cell number (renal tumors)

Question 49

List 3 clinical signs of neoplastic hyperviscosity

Answer 49

1. PU/PD 2. CNS depression 3. Ocular changes

Question 50

Describe the pathophysiology of neoplastic hyperhistaminaemia

Answer 50

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)

Question 51

Which disease is neoplastic myasthenia gravis associated with?

Answer 51

Thyomas | Also immune mediated diseases

Question 52

In which species do we most commonly see cutaneous paraneoplastic syndromes? | How does it present?

Answer 52

Cats | Presents as alopecia or exfoliative dermatitis

Question 53

List 4 tumors with which you will see peripheral neuropathies

Answer 53

1. Insulinoma 2. Carcinoma 3. Sarcoma 4. Melanoma