Chemotherapy

Question 1

How is chemotherapy administered and why?

Answer 1

IV
Oral

For systemic delivery/absorption

Question 2

Name six types of cytotoxic agents

Answer 2

• alkylating agents (act on DNA synthesis)
• antimetabolites (act on DNA itself)
• mitotic inhibitors
• antibiotics
• intercalating agents (act on DNA transcription/duplication)
• spindle poisons (act on mitosis)

Question 3

How do alkylating agents work?

Answer 3

• alkyl groups allow covalent bonds with other molecules
• DNA helix cross-links intra/interstrand
• attaches free guanines on separated DNA strands
• alkyl/methyl groups added to guanines where they don’t belong
• inhibits correct orientation in base pairing
• causes DNA damage/mutation
• prevents DNA replication

Question 4

What are the resistance mechanisms of alkylating agents?

Answer 4

• increased/decreased agent exit/entry
• inactivation of agent inside the cell
• enhanced repair of DNA lesions

Question 5

How o antimetabolites work?

Answer 5

• similar structure to substances required by cell prior to division
• induce cell death in S phase when incorporated into nuclear material

OR

• bind to vital enzymes to inhibit cell division

Question 6

How so vinka alkaloids work?

Answer 6

• stops metaphase
• binds to tubuli
• blocks microtubule/spindle formation

Question 7

How do taxanes work?

Answer 7

• stabilise microtubule bonds to prevent them changing in size during mitosis

Question 8

Name two types of antimitotic antibiotics

Answer 8

• anthracyclines

- non-anthracycliines

Question 9

Give examples of the effects antimitotic antibiotics can have?

Answer 9

• inhibit DNA/RNA synthesis
• increases membrane permeability to ions
• free radicals disrupt DNA chain and prevent mitosis

Question 10

What is the overall effect of antimitotic antibiotic action?

Answer 10

stops DNA replication, causing part of it to cleave off causing cel death

Question 11

What are the main principles of combination therapy?

Answer 11

Combine those with;

• different mechanisms (synergistic/additive/decreased risk of resistance)
• dissimilar toxicity (each administered to maximum tolerated dose)

Question 12

Give some side-effects of chemotherapy

Answer 12

• alopecia
• pulmonary fibrosis
• cardiotoxicity
• renal failure
• myelosuppression
• neuropathy
• myalgia
• diarrhoea
• nausea
• vomiting

Question 13

Name three examples of other systemic cancer treatments

Answer 13

• hormonal drugs (anti-oestrogen Tamoxifen/anti-androgen in prostate cancer)
• targeted against EGFR/VEGF
• immunotherapy