Chemotherapy Flashcards
In what stage of the cell cycle do chemo and radiotherapy work?
They won’t work when the cell is in G0 phase, they only work when the cell is active,y dividing in the mitosis phase.
There are some drugs that try to keep the cells in the cell cycle so the chemo can work.
What is the fractional cell kill hypothesis?
This is where you give a bolus of chemo and this will hit both the tumour cells and other rapidly dividing cells (including cells of the bone marrow)
Bone marrow cells recover more quickly than the cancer cells
Want to time the next dose when the bone marrow cells have recovered but the tumour cells haven’t recovered.
What is meant by chemo sensitivity and give some examples…
Highly sensitive= germ elk tumours/small cell lung/ lymphomas
Modest= breast/bladder/ovary/cervix
Low sensitivity= prostate, renal cell, brain tumours and endometrial.
How do anti metabolites work for chemo, and give some examples…
Anti metabolites act on the DNA synthesis.
5-flurouracil (inhibits thymidylate synthase)
Methotrexate= dihydrofolate reductase inhibitor, folate production affected so cant produce DNA
What are the drugs acting as spindal poisons?
Tax assessor
Ie: paclitaxel
This is a microtubule depolarisation inhibitor, it promotes the assembly of spindles and inhibits disassembly resulting in DNA damage and cell death.
Vinca alkaloids
Ie: vincristine
This is a microtubule assembly inhibitor which prevents the formation of spindles.
How does cisplatin work?
Cisplatin is a platinum compound which inhibits DNA synthesis
What are the side effects of chemo?
Alopecis Hcositis Nausea/vomiting (due to the rapidly dividing cells in the gut) Pulmonary fibrosis Cardiotoxicity Local reaction Rena, failure lmyelosuppressiin Phlebitis MyLgia Cystitis Diarrhoea NeuropThh.
There are important drug interactions with chemotherapy, give examples…
So other drugs may increase the plasma level of the chemo drug and therefore the side effects
An example
Methotrexate with penicillin and NSAIDS
You should monitor chemotherapy drugs, how do you do this?
Response of the cancer- radiological imagine/ tumour marker blood tests
Bone marrow/cytogenetic
Drug levels is: methotrexate drug assays are taken on serial days to ensure the clearance from the blood after the folinic acid rescue.
Checks for organ damage- creatinine clearance (monitoring renal function) and echocardiogram (some drugs cause heart problems).
What do the following mean... neoadjuvant Adjuvant Salvage Palliative Primary
Neoadjuvant = given before surgery Adjuvant= given after surgery to excise the primary cancer, aiming to reduce the relapse risk Palliative= to treat current or anticipated symptoms without a curative intent. Primary= 1st line treatment of cancer Salvage= chemo for relapsed disease
What is cyclophosphamide (used in chemo)?
A cytotoxic agent, it is an pro drug which is converted in the liver to its active forms.
The problem with alkylation gets agents is cancer cells can grow resistance to them.
