10) Chemotherapy Flashcards
What are the different levels of tumour spread?
Local - surrounding structures
Lymphatic - carcinoma
Blood - sarcoma
Implantation - mechanical spread of tumour cells e.g. in chest drain
What are some options for chemotherapy use in patients?
Primary treatment (radical)
Adjuvant
Neoadjuvant
Palliative
When is chemotherapy used as radical treatment?
Lymphomas and leukaemia
What is adjuvant therapy?
Post-op treatment in a patient at high risk of microscopic metastases
What is neoadjuvant therapy?
Primary treatment of patients with a clinically localised tumour, reduce size for easier removal
What is the fractional cell kill hypothesis?
Chemotherapy given in fractionated doses to minimise damage to normal cells as they have time to recover
Give examples of cytotoxic agent classes:
Antimetabolites
Alkylating agents
Intercalating agents
Spindle poisons
What is the mechanism of action of platinum compounds?
Platinated intra and interstrand adducts leading to inhibition of DNA synthesis
What is the mechanism of action of topoisomerase inhibitors?
Inhibit the toposiomerase enzyme that unravels supercoiled DNA. Induces strand breaks leading to apoptosis
What is the mechanism of action of anti-metabolites?
Interfere with purine and pyramidine synthesis
Describe the treatment, Xeloda (campecitabine):
Treatment that is only activated in the tumour to produce 5-FU
What is the mechanism of action of spindle poisons?
Inhibit polymerisation of spindle microtubules
Stimulate polymerisation and prevent depolymerisation of spindle microtubules
What is the aim of combination therapy?
To provide increased efficacy using drugs with different modes of action that require different mechanisms to become resistant
How is P-glycoprotein involved in resistance to chemotherapy?
Efflux of cytotoxic agents out of cells
What are some mechanisms of resistance to chemotherapy?
Enhanced repair of DNA lesions
Efflux of drug
Inactivation of agent in cell
Modified target