Radiotherapy

Question 1

Role of radiotherapy in cancer treatment:

Answer 1

Radiotherapy is a type of cancer treatment that uses high-energy radiation to kill cancer cells and shrink tumours.
- Neoadjuvant, adjuvant, palliative.

Question 2

3 main delivery methods of radiotherapy:

Answer 2

External beam
Brachytherapy
Systemic

Question 3

What are the different types of external beam radiotherapy?

Answer 3

Stereotactic
Proton beam therapy
Gamma knife
Intensity modulated radiotherapy

Question 4

When is proton beam therapy used and what is the benefit?

Answer 4

1. Highly specific for tumours located near critical structures.
   
   2. Use: Paeds, CNS, intraocular malignancies.

Question 5

Skim summary of stereotactic radiotherapy:

Answer 5

Stereotactic radiotherapy (SBRT) or stereotactic radiosurgery (SRS) refer to stereotactic radiation treatments in 1-5 fractions on specialized linear accelerators, using sophisticated imaging, treatment planning, and immobilization techniques. Respiratory gating may be necessary for motion management, e.g. lung tumors. SBRT is used for a number of sites, including the spine, lung, liver, brain, adrenals, and pancreas.

Question 6

What is brachytherapy?

Answer 6

Radioactive source directly into or near the tumour. = High dose to target, low dose to surrounding tissue. The radiation is delivered from inside the body and is usually placed inside needles, seeds, wires or catheters.

Question 7

What is systemic radiotherapy?

Answer 7

This type of radiation therapy involves using radioactive substances that can be swallowed, injected, or inhaled. The radioactive substance then travels through the bloodstream to reach cancer cells throughout the body.

Radionuclides can be used to target specific tumours in specific location e.g thyroid cells accumulate iodine -131.

Question 8

Key principle of radiotherapy:

Answer 8

Tumour to receive the maximum possible dose, while normal tissues receives a dose within tolerance limits.

Question 9

What is meant by fractionation in radiotherapy?

Answer 9

• Diving the total dose into small daily fractions given over several weeks.
• Fractionation spares normal tissue through repair and repopulation while increasing damage to tumour cells through redistribution and reoxygenation.
• The dividing cells are more radiosensitive hence radiotherapy is a good treatment option.

Question 10

How is radiotherapy dose measured?

Answer 10

• The absorbed dose is the quantity of radiation absorbed per unit mass of absorbing material. The modern unit is the Gray (Gy), and is defined as 1 joule absorbed/kg.

Question 11

List of cancers radiotherapy is used in:

Answer 11

Radiotherapy plays a major role in the management of breast, prostate, lung, ano-rectal, oesophagus, head and neck, brain, skin, gynecologic, lymphomas, bladder cancers, and sarcomas.

Question 12

What role does radiotherapy play in palliative care?
(skim)

Answer 12

Spinal cord compression
Vascular compression e.g SVC
Bronchial obstruction
Bleeding from GI tumours
Bleeding from gynaecological tumours
Oesophageal obstruction
Bone pain from mets

Question 13

Side effects of radiotherapy:
- see high yield slide on notion

Answer 13

FATIGUE
Varies depending on the type and location of the cancer being treated. Some of the common side effects of radiotherapy include fatigue, skin changes, hair loss, nausea, and diarrhoea. In addition, radiotherapy can weaken the immune system, making it more vulnerable to infection.

Question 14

Side effects of radiotherapy to the prostate:

Answer 14

Impotence, urinary symptoms, diarrhoea.

Question 15

Side effects of radiotherapy to the head and neck:

Answer 15

Dry mouth, mucositis, taste alteration, skin redness.