Central Nervous System
Etiology
Multiple factors contribute to long term neurocognitive problems in survivors of childhood cancer2:
- Young age at the time of therapy
- The younger a child is, then the more potential there is to damage CNS development.
- Treatment with radiation therapy (RT). Especially if the treatment is:
- High dose
- Given to a large volume of supratentorial brain
- RT induced vasculopathy
- Perioperative complications
- Infection
- Hemorrhage
- Hydrocephalus (probable mild effect)
- Chemotherapy (especially methotrexate)
These factors can be thought of in terms of those relating to the tumor, the treatment and the patient (some of these overlap)
Tumor factors:
- Children with leukemia are at risk for damage both from chemotherapy and RT
- Children with brain tumors are at even greater risk
- Magnitude of risk depends on location and extent of underlying tumor (RT to large volumes of supratentorial brain more likely to be associated with neurocognitive delay).
- Tumors may be associated with structural damage and hydrocephalus which could contribute to generalized brain damage.
- Little evidence from studies that the effect of hydrocephalus is very significant.
Treatment factors:
- Radiation therapy (RT)
- Chemotherapy
- Surgery
- Injury – for example posterior fossa surgery can result in cerebellar mutism
Patient factors:
- Age
- Younger children are at significant risk
- Gender
- Girls appear to be more vulnerable
- Genetic
- Some patients have underlying genetic problems such as ataxia-telangectasia which affect repair of RT induced damage to DNA .
Cognitive decline is usually progressive over at least a decade.
