Radiotherapy

Question 1

How does radiotherapy work?

Answer 1

Ionising radiation causes damage to DNA which prevents cell division and leads to death

Question 2

What is radical radiotherapy?

Answer 2

Given with curative intent

Question 3

What is palliative radiotherapy

Uses?

Answer 3

Aims to relieve symptoms
Smaller doses in fewer fractions
Short term tumour control with minimal side effects

Used for brain mets, spinal cord compression, visceral compression and bleeding

Question 4

What are early reactions to radiotherapy?

Answer 4

2 weeks into treatment

Tiredness
Skin reactions - erythema, dry desquamation, ulceration
Mucositis - Avoid smoking, antiseptic mouthwash, aspirin gargle
N/V - metoclopramide, domperidone, ondansetron
Diarrhoea - maintain good hydration, loperamide after loos stools
Dysphagia - SALT, nutrition
Cystitis - lots of fluid

Question 5

What are late reaction to radiotherapy?

Answer 5

months-years

CNS/PNS
Somnolence, spinal cord myelopathy, bracial plexopathy

Lung - pneumonitis

GI - xerostomia, benign oesophageal strictures

GU - urinary frequency, vaginal stenois, erectile dysfucntion

Endocrine - panhypopituitarism

Secondary cancers - breast screening

Question 6

What are methods of delivering radiotherapy?

Answer 6

External beam radiotherapy - beams of ionizing radiation to the patient from external accelerator

Stereotactic radiotherapy - highly accurate EBRT to target small lesions (Gamma Knife)

Brachytherapy - radiation source placed within or close to tumour allowing high local raidaiton dose

Radioisotope therapy
Tumour seeking radionucleotides target specifc tissue e.g. radioiodine for thyroid cancer