Chemotherapy

Question 1

Name and describe the 4 main stages of the cell replication cycle.

Answer 1

• Growth phase 1 (G1): cell growth. The cell is metabolically active and protein synthesis occurs. No DNA replication occurs within this phase.
• S phase: synthesis stage where DNA replication occurs. DNA helicase unwinds the DNA strands and DNA polymerase extends the DNA chain. Topoisomerase prevents the supercoiling of DNA during the cell replication process.
• Growth phase 2 (G2): cell growth and protein synthesis in preparation for mitosis.
• M phase: mitosis

Question 2

Name and describe the 5 stages of mitosis.

Answer 2

• Prophase: condensation of chromosomes and the beginning of the formation of microtubules. Centromeres migrate to the poles of the cell to form mitotic spindles.
• Prometaphase: nuclear membrane breakdown and attachment of microtubules to the chromosomal kinetochores.
• Metaphase: chromosomes migrate to the equatorial centre of the cells with centromeres at the poles of the cells.
• Anaphase: separation of daughter chromatids by depolymerisation of microtubules.
• Telophase: reassembly of the nuclear membrane with the disassembly of microtubule complexes. Decondensation of chromosomes occurs.

Question 3

Define neutropenic sepsis.

Answer 3

Neutropenic sepsis is defined by NICE as a neutrophil count of 0.5 × 109 per litre or lower, plus one of the following:

Temperature ≥ 38°C or
Other signs or symptoms consistent with significant sepsis

Question 4

Why do patients being treated with chemotherapy experience mucositis, malabsorption and diarrhoea?

Answer 4

Increased apoptosis within the rapidly dividing epithelial cells in the oral mucosa and intestine causes mucosal damage throughout the gastrointestinal tract.

Question 5

Why do patients being treated with chemotherapy experience nausea and vomiting?

Answer 5

The direct effect of some chemotherapy agents on the chemoreceptor trigger zone within the medulla

Question 6

Why do patients being treated with chemotherapy experience hair loss?

Answer 6

Chemotherapy-induced damage to the rapidly dividing cells in the hair root results in hair loss.

Question 7

Name 3 methods of classifying chemotherapy agents.

Answer 7

1. Origin
2. Mechanism of action
3. Site of action

Question 8

Describe the mechanism of action of antimetabolites.

Answer 8

Antimetabolites act by replacing the natural building materials needed for DNA and RNA synthesis. This prevents DNA replication, halting cell reproduction.

Antimetabolites act on the S phase of the cell cycle.

Question 9

Describe the mechanism of action of pyrimidine antagonists.

Answer 9

Pyrimidine antagonists inhibit thymidine synthase. This prevents the synthesis of the thymidine nucleotide, halting DNA replication.

Question 10

Name a specific side effect associated with Pyrimidine antagonists.

Answer 10

Palmar plantar erythrodysesthesia (PPE)

Question 11

What is Palmar plantar erythrodysesthesia (PPE)?

Answer 11

PPE is a painful erythematous rash occurring over the palms, fingers and soles of the feet. Lesions are typically clearly demarcated and painful. Skin breakdown and blistering typically develop as the condition progresses.