Flashcards in Treating Cancer Deck (17):
Define the term cancer?
When cells no longer responded to signals that control survival, proliferation and differentiation.
Small population of tumour cells in a tumour mass and repeated division.
What are the two types of cancer?
Malignant- rapid growth, invades and destroys tissues and can perform metastasis.
Benign- no metastasis, slow growth, compresses surrounding tissues.
Where are a) carcinoma, b) sarcoma and c) leukaemia located?
a) epithelial cells
b) connective tissues
c) haemopoetic tissues
What are the three types of chemotherapy?
Maintenance- low dosages to prolong remission
What are the two types of anti cancer drugs?
Cell cycle specific: anti metabolites (effective for high growth tumours)
Cell cycle non-specific: alkylating agents (effective for slow growth tumours)
What are the problems with chemotherapy?
Pharmacological sanctuaries are not reached- some tumours 'hide' behind the BBB.
Resistance- can be inherited or acquired.
Adverse effects- vomiting, ulcers, alopecia, diarrhoea, growth retardation etc.
In leukaemia's what does the replacement of bone marrow with malignant cells cause?
Deficiency in erythrocytes and white cells, loss of platelets.
What may be induced by anticancer drugs?
Resting cell division
What are the 6 hallmarks of cancer?
1) self-sufficient ingrowth signals
2) insensitive to antigrowth signals
3) tissue invasion and metastasis
4) unlimited replicative potential
5) sustained angiogenesis
6) evasion of apoptosis.
What are three types of anticancer dugs?
Cytotoxic (alkylating agents, anti metabolites, cytotoxic antibiotics and plant derivatives) , hormones (suppression of secretion) and others (newer drugs, eg. Tumour specific ones).
What is the most common cytotoxic anticancer drug?
How do alkylating agents work?
Form covalent bonds with DNA, form carbonium ion (6 electrons in the outer shell around carbon, create a highly reactive electron donor), formation of cross linking and interferes with transcription and replication.
Give and example of an alkylating agent?
Nitrogen mustard- clyclophosphamide
Inactive until metabolised by liver P450 oxidases
Oral and IV administration
Has all of the usual unwanted effects
What are the functions of folates and how do anti metabolites work?
Synthesis of purine nucleotides and thymidylate. Their main action is to interfere with the thymidylate synthesis.
What is the most common folate antagonist anti metabolite?
What are the benefits of methotrexate?
Can be administered orally (or IV or IM), has little CNS activity due to low lipid solubility, readily taken into cells via folate transport system and long lasting effects