L13: radiotherapy and approaches to cancer treatment

Question 1

What is brachytherapy?

Answer 1

• Brachytherapy is when radio isotopes are used to treat a tumour by placing the source close to the tumour – Iodine 192

Question 2

What is adjuvant?

Answer 2

Post-operative

Question 3

What is neoadjuvant?

Answer 3

pre-operative

Question 4

What is salvage?

Answer 4

early localized reccurece

Question 5

What are the phases of radiotherapy?

Answer 5

• Physical phase – energy deposition, ionization/excitation
• Chemical phase – indirect effect / free radical reactions, chemical modification
• Biological phase – cellular effects (enzymatic repair, expression of damage, mutation, transformation cell killing); tissue effects – early (intestine / haemopoietic); tissue effects – late (fibrosis / spinal cord); whole organism (carcinogenesis / death)

Question 6

What is the interaction of radiation with DNA?

Answer 6

Interaction of radiation with DNA
- 80% via indirect effect via hydrolysis of water
- 20% direct effect via direct interaction with DNA
- Deposition of energy – photons / protons / charged particles / electrons interacting with biological structures creates the radiation dose