Anti Cancer Drug Therapy

Question 1

How does Chemotherapy work?

Answer 1

Cancer drugs are primarily cytotoxic so interfere with cell growth and division to induce apoptosis of cells

Question 2

Which cells do Chemotherapy drugs primarily target?

Answer 2

Fast dividing cells

Question 3

What is induction chemotherapy?

Answer 3

chemotherapy that aims to shrink or reduce a tumour

Question 4

What is consolidation chemotherapy?

Answer 4

to maintain the size- ensure it doesn’t grow any further

Question 5

What is adjuvant chemotherapy?
And how is it different to Neo-adjuvant therapy?

Answer 5

used after another therapy to amplify the original therapy
Neo- used to shrink before surgery

Question 6

Which cells are resistant to Chemotherapy?

Answer 6

Cells in the G0/ the resting phase are relatively resistant

Question 7

What is the maximum tolerated dose?

Answer 7

the highest dose that most patients can tolerate- kills of a fixed percentage of cells rather than ALL cells

Question 8

Why would we pulse chemotherapy doses at intervals?

Answer 8

to make time for normal tissue recovery whilst preventing tumour regrowth

Question 9

How is the chemotherapy dosing calculated?

Answer 9

can dose for body surface area (mg/m2) with a conversion chart but this can lead to overdosing so…
Dose for mg/kg

Question 10

In combination Chemotherapy- what do we consider when choosing the drugs?

Answer 10

• need drugs that are effective as single agents
• that the drugs don’t interfere with each other
• that the drugs don’t have overlapping toxicities e.g. both causing GIT damage= extra GIT damage inflicted

Question 11

Give three examples of Combination Chemotherapy’s and what they’re used for.

Answer 11

CHOP based protocols- feline lymphoma
COP based protocols- canine lymphoma
LOP/LOPP based protocols- when lymphoma relapses

Question 12

What is Metronomic Chemotherapy?

Answer 12

administration of regular low, daily dose of cytotoxic agents that act on the tumour microenvironment to prevent tumour blood vessels forming and therefore induce tumour dormancy

Question 13

What is targeted therapy in terms of cancer treatment?

Answer 13

Use of Masitinib or Toceranib Phosphate which are tyrosine-kinase inhibitor- Tyrosine kinases help to send growth signals in cells, so blocking them stops the cell growing and dividing

Question 14

Can Cancer develop resistance to Chemotherapy?
If so, how?

Answer 14

Yes- because tumours are genetically unstable, the drug exposure selects resistant cells which upregulate the MDR1 gene- Upregulation of MDR1 is linked to chemoresistance

Question 15

What are some common SYSTEMIC adverse effects of Chemotherapy?

Answer 15

Organ dysfunction
Myelosuppression- Immune suppression & Thrombocytopenia
Gastrointestinal toxicity
Cardiotoxicity
Cystitis

Question 16

How does Chemo cause immunosuppression?

Answer 16

Targets neutrophils- as these are the fastest dividing

Question 17

What is the Nadir and when is the neutrophil nadir during Chemo?

Answer 17

Nadir= lowest cell count
Occurs 7 days post chemotherapy

Question 18

What is the nadir for platelets during Chemo?

Answer 18

10 days post chemotherapy

Question 19

How do we limit/treat the myelosuppressive effects of Chemotherapy?

Answer 19

Delay chemo and retest CBC if still neutropenic after 7 days- give antibiotics if the neutrophil count is less than 0.75 (normal is 3-12) and if patient is showing signs of illness
Consider chemotherapy dose reduction

Question 20

For GI toxicity during Chemo, when would we consider giving antibiotics?

Answer 20

If patient has-
Haemorrhagic diarrhoea
Persistent diarrhoea

Question 21

What is Drug Extravasation?

Answer 21

leakage of injected drugs from the blood to the tissues causing damage- usually appears near injection site

Question 22

How do we treat drug extravasation?

Answer 22

Try aspirate the drug
Can also use hot compresses or Ice depending on the chemo drug used

Question 23

What are some adverse effects associated with the Chemo drug Vincristine? (2)

Answer 23

Peripheral neuropathy
Ileus (paralysis of the bowel)

Question 24

Which Chemo drugs have an increased risk of Nephrotoxicity?

Answer 24

Carboplatin
Lomustine