Anti Cancer Drug Therapy Flashcards
How does Chemotherapy work?
Cancer drugs are primarily cytotoxic so interfere with cell growth and division to induce apoptosis of cells
Which cells do Chemotherapy drugs primarily target?
Fast dividing cells
What is induction chemotherapy?
chemotherapy that aims to shrink or reduce a tumour
What is consolidation chemotherapy?
to maintain the size- ensure it doesn’t grow any further
What is adjuvant chemotherapy?
And how is it different to Neo-adjuvant therapy?
used after another therapy to amplify the original therapy
Neo- used to shrink before surgery
Which cells are resistant to Chemotherapy?
Cells in the G0/ the resting phase are relatively resistant
What is the maximum tolerated dose?
the highest dose that most patients can tolerate- kills of a fixed percentage of cells rather than ALL cells
Why would we pulse chemotherapy doses at intervals?
to make time for normal tissue recovery whilst preventing tumour regrowth
How is the chemotherapy dosing calculated?
can dose for body surface area (mg/m2) with a conversion chart but this can lead to overdosing so…
Dose for mg/kg
In combination Chemotherapy- what do we consider when choosing the drugs? (3)
- 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
Give three examples of Combination Chemotherapy’s and what they’re used for.
CHOP based protocols- feline lymphoma
COP based protocols- canine lymphoma
LOP/LOPP based protocols- when lymphoma relapses
What is Metronomic Chemotherapy?
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
What is targeted therapy in terms of cancer treatment?
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
Can Cancer develop resistance to Chemotherapy?
If so, how?
Yes- because tumours are genetically unstable, the drug exposure selects resistant cells which upregulate the MDR1 gene- Upregulation of MDR1 is linked to chemoresistance
What are some common SYSTEMIC adverse effects of Chemotherapy?
Organ dysfunction
Myelosuppression- Immune suppression & Thrombocytopenia
Gastrointestinal toxicity
Cardiotoxicity
Cystitis
How does Chemo cause immunosuppression?
Targets neutrophils- as these are the fastest dividing
What is the Nadir and when is the neutrophil nadir during Chemo?
Nadir= lowest cell count
Occurs 7 days post chemotherapy
What is the nadir for platelets during Chemo?
10 days post chemotherapy
How do we limit/treat the myelosuppressive effects of Chemotherapy?
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
For GI toxicity during Chemo, when would we consider giving antibiotics?
If patient has-
Haemorrhagic diarrhoea
Persistent diarrhoea
What is Drug Extravasation?
leakage of injected drugs from the blood to the tissues causing damage- usually appears near injection site
How do we treat drug extravasation?
Try aspirate the drug
Can also use hot compresses or Ice depending on the chemo drug used
What are some adverse effects associated with the Chemo drug Vincristine? (2)
Peripheral neuropathy
Ileus (paralysis of the bowel)
Which Chemo drugs have an increased risk of Nephrotoxicity?
Carboplatin
Lomustine
