Late effects of treatment on the intelligence of children with posterior fossa tumors.

This retrospective pilot study was undertaken to evaluate the late effects of treatment on intelligence in a population of children with posterior fossa tumors. Ten children with posterior fossa tumors treated with radiation and chemotherapy received intellectual evaluations at least one year following diagnosis. Six children had medulloblastomas, one child had a fourth ventricular ependymoma, two children had brainstem gliomas, and one child had a recurrent cerebellar astrocytoma. Children with supratentorial tumors were specifically excluded from the study in order to eliminate the possible influence of the tumor on intellectual functioning. Four children had had intelligence testing in school prior to treatment of their tumor. In each case results following treatment revealed a deterioration of full scale IQ of at least 25 points. Six children did not have prior testing; of these, two had IQ's less than 20. Overall, 50% of the patients had IQ's of less than 80 and 20% had IQ's of greater than 100. Furthermore, four children with normal intelligence (IQ greater than 80) have learning problems requiring special classes. Thus, of the ten children evaluated, all have either dementia, learning disabilities, or evidence of intellectual retardation. This study suggests that aggressive treatment of children with brain tumors may improve survivals but may be associated with significant long-term disabilities.