12. Cancer Chemotherapy Flashcards
At what point of a tumour’s growth should chemotherapy be used?
When it’s a detectable cancer, limited time scale.
What are the implications on chemotherapy of fractional cell kill hypothesis?
Need to administer drugs close enough together that tumour cells don’t fully recover by far enough away that the cells of bone marrow have time to recover (quicker than tumour cells).
Name a tumour that’s highly sensitive to chemotherapy.
Lymphomas, germ cell tumours, small cell lung, neuroblastoma, Wilm’s tumour.
Name a tumour that has modest sensitivity to chemotherapy.
Breast, colorectal, bladder, ovary, cervix.
Name a tumour that has low sensitivity to chemotherapy.
Prostate, renal cell, brain tumours, endometrial.
What are the sites of action of cytotoxic agents?
DNA synthesis, DNA, DNA transcription/duplication, mitosis.
What is the mechanism of action of alkylating agents?
Bonds lock two strands together so they can’t be unwound to replicate so the cell dies/
What is the mechanism of action of antimetabolites?
Impacts thymidylate synthase or dihydrofolate reductase so it blocks the folate cycle. Purine/amino acids can’t be formed.
What is the mechanism of action of spindle poisons?
Once chromosomes are aligned at metaphase plate, spindle microtubules depolymerise, moving sister chromatids towards opposite poles. Nuclear membrane reforms and cytoplasm divides. Binding to microtubules affects dynamics - inhibits polymerisation or stimulates polymerisation and prevent depolymerisation.
What is the mechanism of action of spindle poisons at a cellular level?
Taxoids promote assembly and prevent disassembly, vinca alkaloids prevent spindle formation.
What is the mechanism of resistance to alkylating agents?
Decreased entry or increased exit of agent, inactivation of agent, or enhanced repair of DNA lesions from alkylation.
What are the indications for chemotherapy?
Cancer; predicted response based on performance score, clinical stage, prognostic factors, molecular or cytogenetic markers; side effects vs anticipated or best outcome.
What are the routes of administration for chemotherapy?
IV most commonly, PO, SC, into body cavity, intralesional, intrathecal, topical, IM.
What are the ADRs of chemotherapy?
Acute renal failure, GI perforation at site of tumour, disseminated intravascular coagulopathy, vomiting, alopecia, skin toxicity, mucositis, cardio-toxicity, lung toxicity, haematological toxicity.
What are the patterns of emesis seen with chemotherapy treatment?
Acute phase 4-12 hours, delayed onset 2-5 days, chronic phase <14 days.
