Risk factors for cognitive decline in children treated for brain tumors.

The long term effects of central nervous system therapy for children with brain tumors have been the subject of research since the 1970s. Many studies have demonstrated that children treated for brain tumors with surgery and standard radiation therapy have developed intellectual decline which is progressive over at least a decade. Risk factors for this cognitive deterioration have been identified and include perioperative complications, possibly hydrocephalus, high radiation dose, large volume radiation, chemotherapy (especially methotrexate), radiation vasculopathy and young age at the time of treatment. In an effort to reduce long-term neurotoxicity, efforts have been made to develop treatment regimens that reduce the impact of these risk factors. Some of these include reduced neuraxis radiation with and without adjuvant chemotherapy, conformal radiation, chemotherapy only protocols for children with optic pathway-hypothalamic tumors and a series of baby brain tumor studies in which chemotherapy (standard and high dose) has allowed radiation to be delayed, reduced or omitted. Whether these changes in therapy will ultimately improve the quality of life of the long-term survivors is uncertain. Close follow-up of these children will be required throughout their lives.