Chemotherapeutics

Question 1

Define a chemotherapeutic agent and 2 the methods of action

Answer 1

A drug used to treat cancers
By:
- Causing cell death
- Stopping cells from dividing

Question 2

Name the routes of administration of a chemotherapeutic drug

Answer 2

Oral
Injection
IV infusion - most common
Topical

Question 3

Why is topical treatment problematic in veterinary patients

Answer 3

They groom themselves => ingestion of the agent

Question 4

Name the 2 types of chemotherapeutic agents

Answer 4

1. Cytotoxic drugs
2. Targeted therapy

Question 5

How do cytotoxic drugs work, what tumours are they effective against and give some examples

Answer 5

They inhibit mitosis and/or damage DNA
Kill rapidly dividing cells
Good against neoplastic cells, can attack GI epithelial cells or bone marrow cells = bad
Examples - Vincristine, doxorubicin, chlorambucil, cyclophosphamide

Question 6

What specific things can targeted therapy target

Answer 6

Receptors
Signalling pathways
Antigens

Question 7

Give some examples of targeted therapy and what the drugs used are called

Answer 7

Tyrosine kinase inhibitors for mast cell tumours
- Masitinib, toceranib
Monoclonal antibodies vs specific tumour antigens

Question 8

Is clinical toxicity an issue with targeted therapy

Answer 8

Yes

Question 9

Give 4 limitations cytotoxic drugs

Answer 9

1. Palliative not curative
2. Toxicity limits dose/frequency of dose
3. Maximum tolerated dose - highest dose with ‘acceptable’ side effects
4. Metronomic chemotherapy (MC)

Question 10

What is the aim of Metronomic chemotherapy (MC) and how is it achieved

Answer 10

Aim is to delay or slow disease progression, not kill cancer cells
Inhibiting angiogenesis
Modulating immune response to cancer cells

Question 11

What balance do vets have to get right when using chemotherapeutic drugs

Answer 11

Maximising the benefit whilst minimising the harm

Question 12

How do vets maximise the benefits of chemotherapeutic drugs

Answer 12

Treat small tumours with a high growth fraction
Cell cycle-specific drugs kill a limited number of cells each dose => need to use a combo of drugs to target different phases of the cell cycle

Question 13

Name 2 ways in which chemotherapeutic drugs can do harm to people

Answer 13

1. Direct exposure to the drugs
2. Metabolites of the drugs excreted by pets can also be harmful