chemo drugs Flashcards
describe a benign tumour
lacks invasive properties, unable to metastasize, can suppress vital organs
describe a malignant tumour
causes loss of organ function, invasive, ability to metastasize
describe the cell cycle
mitosis (M) –> growth phase (G1) –> cells no longer dividing (Go) –> DNA synthesis (S) –> further cell division in second growth phase (G2)
what is a proto-oncogene?
a normal gene that has the potential to lead to cancer - it can mutate to become an oncogene.
objectives of cancer therapy:
cure the patient and eliminate all cancer cells, prolong life by shrinking tumour and alleviating symptoms, palliative therapy to reduce pain and improve quality of life
symptoms of cancer?
pain - due to compression of nerves, inhibition of organ function, detection of a solid mass (lump),
what are the three ‘compartments’ that a cell occupies in a tumour?
1 - diving cells; susceptible to cytotoxic drugs
2 - resting cells (in Go phase of cell cycle) but capable of dividing
3- cells no longer dividing
why can we not rely on the immune system to kill remaining cancer cells?
the immune system is unable to recognise tumour cells as foreign - because essentially they are normal cells that have undergone uncontrolled proliferation
toxic effects of chemotherapy?
bone marrow suppression (reduced RBC and WBC), impaired wound healing, hair loss (due to hair follicles rapidly dividing), damage to GI epithelium, stunted growth, sterility, teratogenicity, bleeding/bruising (due to lack of platelets and clotting factors), nausea, vomiting, kidney damage
targets for anti-cancer drugs?
hormonal regulation of tumour growth, defective cell cycle controls
what are the main classes of anti-cancer drugs?
cytotoxic drugs, hormones, monoclonal antibiotics, protein kinase inhibitors
examples of cytotoxic drugs?
alkylating agents, antimetabolites, antibiotics, plant derivatives
examples of alkylating agents?
nitrogen mustards, nitrosaureas, platinum compounds
function of alkylating agents?
target cells in the DNA synthesis phase to form covalent bonds with DNA and prevent uncoiling and inhibit replication
side effects of prolonged use of alkylating agents?
sterility esp in men, increased risk on non-lymphocytic leukaemia
examples of antimetabolites?
folate antagonists e.g. methotrexate, pyrimidine analogues e.g. fluorouracil, and purine analogies
function of methotrexate?
inhibits dihydrofolate reductase, an essential enzyme for DNA synthesis.
function of pyrimidine analogues?
inhibits DNA synthesis by competing with C and T bases of RNA and DNA.
function of purine analogues?
compete with A and G bases to inhibit purine metabolism
examples of cytotoxic antibiotics?
doxorubicin, bleomycin, dactinomycin, mitromycin
side effects of doxorubicin?
can cause cardiac dysrhythmias and heart failure with high doses
side effects of bleomycin?
myleosupression, pulmonary fibrosis (10% of patients) and mucocutaneous reactions (50% of patients)
what are vinca alkaloids?
plant derivatives. e.g. vincristine, binblastine, vindesine
when do vinca alkaloids work?
during the mitosis phase of the cell cycle