Acute & Late Effects of RT

Question 1

acute effects of RT

Answer 1

• transient worsening of symptoms due to oedema
• brainstem/posterior fossa RT: significant nausea and vomiting, otitis externa
• alopecia in irradiated area
• radiation dermatitis
• mucositis, oesophagitis and myelosuppression in CSI
• fatigue
  Acute effects subside within 4-6 weeks post RT and are dose-related

Question 2

subacute effects of RT

Answer 2

• somnolence
• fatigue
• neurologic deterioration (? caused by changed in capillaries and transient demyelination)
  subacute effects last from 6 weeks to 6 months post-RT

Question 3

Late effects of RT

Answer 3

• Radiation necrosis
  -> can mimic recurrence
  -> develops as a focal process at or near the tumour site
  -> grographically associated with the region of highest dose
  -> incidence ranges from 5% to 24% (Kumar et al.)
  -> lesion type also a predisposing factor, most likely with gliomas than brain metastases (Loeffler et al., Shaw et al)
• cataract formation and retinopathy if eye treated
• changes in visual acuity/blindness if optic chiasm/optic nerve treated to >54Gy
• neuropsychological changes
• Lhermittes’ syndrome post spinal treatments
• spinal deformity in children
• focal effects to thyroid, heart, bowel, ovaries
• hearing loss
• endocrine abnormalities

late effects occur from 6 months to many years post-RT

Question 4

Follow up

Answer 4

Imaging
- MRI performing 1 month after RT shows increased enhancement in 40% of cases
- About half of these are due to a transient increase in vessel permeability: ‘pseudoprogression’