chemotherapy Flashcards
cancer treatment plans
1) surgery
2) radiation therapy (radiotherapy)
3) chemotherapy
a) neo-adjuvant (chemotherapy before surgery/radiation therapy) in case of Hodgkin’s disease
b) adjuvant (chemotherapy after surgery or radiation therapy) in the case of breast cancer.
4) palliative care
chemotherapeutic treatment
The use of drugs (chemicals) to manage the malignancies : Chemotherapy
Cancer cells are similar to host cells so difficult to target
Cancer cells usually rapidly dividing - so target DNA synthesis and mitosis (cell division)
Use Cytotoxic drugs: kill rapidly dividing cells –
Carried out in cycles, with Induction and Maintenance phases
Cytotoxic drugs are dosed based on body surface area (BSA)
why do we give cycles of chemotherapy?
- achieve total cell kill
- limit toxicity
- typically 3 week cycles
- given in cycles to allow bone marrow to recover
cell cycle-specific (CCS) agents
- antimetabolites
- plant alkaloids
cell cycle-nonspecific (CCNS) agents
- alkylating agents
- antibiotics
antimetabolites
CCS agent.
interfere with metabolic pathways in DNA synthesis
- methotrexate (folate antagonist)
- 5-Fluorourcil (pyrimidine antagonist or false substrates)
plant alkaloids
CCS agent.
- vinca alkaloids
- taxanes
- podophyllin alkaloids
methotrexate
CCS agent- antimetabolite.
folate antagonist. inhibits purine synthesis
5-Fluorouracil
CCS agent- antimetabolite.
(false substrate) is a pyrimidine analogue.
incorporated into DNA as false metabolites and lead to damage to the DNA
vinca alkaloids: vincristine
a plant alkaloid.
inhibit the formation of the mitotic spindle
taxanes e.g. paclitaxel
a plant alkaloid.
stabilise spindle fibres producing similar effects to vinca alkaloids
podophyllin alkaloids e.g. etoposide
inhibits topoisomerase II (TOP2) enzyme, which prevents ligation of DNA, leading to breaks in the DNA strand (DNA damage) and eventually cell death
platinum compounds e.g. cisplatin
- alkylating agents, thus CCNS agents
- causes the inhibition of DNA synthesis by cross linking guanine residues
Combination with vinblastine and bleomycin has been a success story for the treating testicular cancer
antibiotics e.g. anthracyclines
- CCNS agents.
- cytotoxic actions:
1) interference with nucleotide synthesis by intercalating between DNA strands.
2) enzyme topoisomerase II enzyme
3) generating free radicals. these free radicals are toxic to the heart.
how to overcome reduced white cell counts
with Granulocyte-colony-stimulating factors (G-CSF) (Bone marrow growth factors)
