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Astrocytoma

 

 

Late Effects

 

Late Effects of Radiation Therapy (RT):

  • Occur 90 days to many years after RT 

The severity of late effects depends very much on:

  • Age of the child at therapy:
    • The younger the child, the more pronounced the toxicity is likely to be
  • Dose of RT:
    • Higher dose associated with increased toxicity
  • RT treatment field extent:
    • Treatment to large volumes of supratentorial brain can be associated with very severe neurocognitive delay
    • Craniospinal RT more damaging than focal field
  • Concurrent chemotherapy increases RT toxicity

The most devastating late effect of therapy for astrocytomas is usually neurocognitive delay.

 

Summary of Late Effects after radiation therapy for astrocytomas:

Therapy Late Toxicity

Cranial RT

 

Neurocognitive problems:

  • Poor short term memory
  • Difficulty with executive function

 

Depression:

  • Usually related to multiple long-term health problems and neurocognitive dysfunction

 

Hearing loss:

  • Direct RT related damage to the cochlea
  • Compounded sometimes by previous cisplatin

 

Pituitary and hypothalamic dysfunction:

 

Increased risk for cerebrovascular events (strokes):

  • RT effect on cerebral vasculature

 

Increased risk of second neoplasms:

 

Orbital and optic apparatus damage:

  • Cataracts are a common problem as the lens of the eye is very sensitive to RT
  • RT to the optic chiasm and optic nerves may cause blindess and optic atrophy

 

Sparse growth of scalp hair:

  • Especially affects the scalp overlying the area where high dose RT was given

 

Hypoplasia (undergrowth) of skull and soft tissues within RT volume

 

Craniospinal

RT (may be given for craniospinal dissemination)

Thyroid damage is very common due to the "exit" dose of the spinal field:

 

Spinal damage from RT effect on spinal growth:

  • Short sitting height (and therefore total height)
  • Scoliosis and kyphosis of spine leading to pain
  • Increased risk of early spinal arthritis and osteoporosis

 

Infertility:

  • Exit dose from lower end of spinal field damages ovaries or testicles

 

Cardiac damage:

  • Valvular stenosis from exit RT exit dose (very rare)

 

Damage to bone marrow reserve:

  • After craniospinal RT, it is very difficult to tolerate further intensive chemotherapy
  • Bone marrow reserve is permanently damaged

 

 

 

Summary of Late Effects after chemotherapy for astrocytomas:

Therapy Late Toxicity
Chemotherapy

Cisplatin associated with:

  • High frequency hearing loss
  • With RT this may cause severe hearing impairment

Vincristine associated with:

  • Peripheral neuropathy

Alkylating agents associated with:

  • Infertility
  • Second malignancies

 

 

 

 

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