Radiotherapy

Question 1

What does radiotherapy do

Answer 1

It uses ionising radiation to cause damage to cause damage to DNA
This prevents cell division and leads to cell death
The aim is to inactivate cancer cells without causing a severe reaction in normal tissue

Question 2

What is radical treatment

Answer 2

Given with curative intent
Total doses range from 40-70 gray in up to 40 fractions
Some regimens involve several smaller fractions day with a gap of 6-8 hours
There can be combined chemo radio in some cancers to inc response rate - anus and oesophagus

Question 3

What is palliative treatment

Answer 3

The aim is to relieve symptoms may not impact on survival
Doses are smaller and given in fewer fractions to offer short term tumour control with minimal side effects
Is used in brain mets, spinal cord compression, visceral compression, bleeding - haemoptysis, haematuria
Bone pain from mets

Question 4

What are the early reactions to radiotherapy

Answer 4

Tiredness
Skin reactions
Mucositis
N/V
Diarrhoea
Dysphagia
Cystitis

Question 5

Late reactions from chemo

Answer 5

CNS/PNS somnolence brain radio
Spinal cord myelopathy - progressive weakness ensure to exclude spinal cord compression.
Brachial plexopathy - numb weak painful arm after axillary radio
Lung - pneumonitis
GI - Xerostomia - reduced saliva, benign structures of oesophagus
Radiation proctitis
Endocrine - panhypopituitarism, following radical tx inc pit fossa
Hypothyroidism after neck tx
Secondary cancers risk low compared to risk of current cancer
Women <35 receive radio for non Hodgkin Lymphoma should receive breast cancer screening from 8 years post tx

Question 6

Methods of delivering radio

Answer 6

Conventional external beam radio
Stereotactic radiotherapy
Brachytherapy
Radioisotope therapy