Cancer Chemotherapy Flashcards
What special characteristics are exhibited by cancer cells?
Uncontrolled proliferation
Loss of original function (anaplasia)
Invasiveness
Metastasis
What types of cancer can be treated by surgical removal?
Solid tumours which have not metastasised
Chemotherapy drugs are specific to cancer cells. T/F?
False - this accounts for their wide range of side effects
What are the general toxic side effects of cancer chemotherapy?
Bone marrow suppression causing anaemia, immune depression, recurrent infections and impaired wound healing Loss of hair Damage to GI epithelium Liver, heart and kidney damage Depression of growth in children Sterility Teratogenicity
Cancer chemotherapy drugs only attack cell division and therefore do not reverse…?
De-differentiaition
Invasiveness
Metastasis
Why do cancer chemotherapy drugs only attack a subpopulation of the cancer cells?
Even in a rapidly dividing cell population, such as in cancers, not all cells are undergoing mitosis at any one time.
Why must chemotherapy aim to kill all malignant cells?
The host immune system does not destroy the remaining cells and so these will divide again and the cancer will recur
Why is it necessary that chemotherapy is a prolonged treatment regimen?
Severe cumulative toxicity is required to ensure all malignant cells are destroyed. Also, chemotherapy only attacks actively dividing cells and only some of the cells in a cancer will be actively dividing at any one time.
What are the main classes of chemotherapy agents?
Alkylating agents Antimetabolites Cytotoxic antibiotics Microtubule inhibitors Steroid hormones and antagonists
How do alkylating agents work as anticancer drugs?
Alkylating agents form covalent bonds with DNA
Most have two reactive groups:
One group acts within one strand of DNA to inhibit transcription
The other group acts across two strands fo DNA to prevent strand separation in DNA replication
Give examples of alkylating agents used in chemotherapy
Cisplatin Temoxolomaide Lomustine Bisulphan Melphalan Cyclophosphoamide
Which alkylating agents is used particularly in the treatment of brain tumours?
Lomustine
Melphalan is a chemotherapy agent used in the treatment of multiple myeloma, ovarian and breast cancers. What is melphalan composed of?
Mechlorethamine infused with phenylalanine
Melphalan is a chemotherapy agent. What cancers is it particularly used to combat?
Multiple myelomas
Ovarian cancer
Breast cancer
How do antimetabolites work to treat cancer?
These interfere with nucleotide synthesis and DNA synthesis
Antifolates are chemotherapy agents which inhibit nucleotide synthesis. Give examples of antifolates.
Methotrexate
Relitrexed
Pemetrexed
Nucleotide analogues inhibit DNA polymerases and so are used as chemotherapy agents. Give examples of these drugs.
5-fluorouracil cytarabine gemcitabine fludarabine capecitabine
Folate antagonists inhibit dihydrofolate formation to prevent to synthesis of which nucleotides?
Purine / pyrimidine
Pyrimidine analogues are chemotherapy agents which prevent the formation of which nucleotide?
Thymidine
Purine analogues are chemotherapy agents. How do purine analogues disrupt DNA?
Converted to false nucleotides which disrupts purine synthesis
Dactinomycin is a cytotoxic antibiotic which is used as a chemotherapy agent. What is its mechanism of action?
Inserts itself into the minor grove in the DNA helix to disrupt RNA polymerase
Doxorubcin is a cytotoxic antibiotic which is used as a chemotherapy agent. What is its mechanism of action
Inserts itself between base pairs, binding to the sugar-phosphate backbone of DNA to cause local uncoiling and impair DNA and RNA synthesis
Microtubule inhibitors are chemotherapy agents which block tubular polymerisation to disrupt cell division. T/F?
True
Give an example of an anti-cancer drug which is an antagonist of the oestrogen receptor?
Tamoxifen
