L22 - Introduction to chemotherapy Flashcards
What is the nuremberg code?
It is a set of research ethical principles for human experimentation. It includes the potentiality for fruitful results based on animal experiments.
What are the main uses of chemotherapy?
Primary induction treatment (first line) - for cancers where it is the most effective form of treatment e.g. testicular caner
Neo-adjuvant therapy - used to debulk a tumour before treatment
Adjuvant - used after treatment to make sure all of the cancer cells are eliminated
Regional treatment - can be given locally
What are some characteristics of malignant cells that are often targets of chemotherapy?
- Dysregulated cell cycle that can be targeted by chemotherapy to cause more cell damage and eventually apoptosis.
- Mitogenic signals - e.g. oestrogen receptor
- Altered gene expression
- Impaired apoptosis
What stages of the cell cycle do cytotoxic chemotherapy agents target?
They target different stages of the cell cycle depending which on what type of agent they are e.g. microtubule inhibitors stop G1/G0 phase
What is apoptosis in response to?
External signalling
DNA damage e.g. via p53
Differentiation
How do Anti-metabolites work as chemotherapy agents, give an example?
Mainly stop synthesis of thymidine which is needed for DNA replication so stops S phase of DNA replication. e.g. 5-fluorouracil
How do anthracyclines work and give an example?
They are planar molecules that intercalate between base pairs of DNA and RNA and prevent replication. e.g. doxorubicin
How do topoisomerase inhibitors work?
They work by inhibiting enzymes that control changes in DNA structure. This causes cell death.
How do microtubule inhibitors work?
Stop formation such as the mitotic spindle resulting in cell death.
How do alkylating agents work?
They affect the selectivity of DNA binding resulting in problems with replication, repair and transcription.
How do platinum analogues work?
Such as cisplatin, work by containing electron carrier groups that determine the structure of DNA adducts.
Why do chemotherapy drugs have a narrow therapeutic index?
Drugs directed against cancer cells may affect normal cells. Need to balance killing cancer cells and not too many normal cells.
What does reversible toxicities refer to?
Cancer drugs affect rapidly dividing cells e.g. hair follicles. Reversibility refers to the time for the compartment to repopulate and ditates the time between cycles.
What is irreversible accumulative toxicity?
Affects slowly dividing cells such as kidneys and heart. Reflects the slow build up of toxicity over time.
