Central nervous system prophylactic treatment for childhood leukemia: neuropsychological outcome studies.

The cognitive sequelae of central nervous system treatments for leukemia have become a major concern as more leukemic children survive the initial consequences of the disease. A review of 28 neuropsychological outcome studies published in the past nine years shows that the preponderance of evidence from the better designed studies suggests that leukemic children who do not suffer overt Central Nervous System (CNS) complications, such as CNS relapse, do not experience significant cognitive deficits as a consequence of their treatment. Also, these studies do not unequivocally suggest that cranial irradiation as a treatment technique results in greater cognitive impairment than treatment without irradiation. Many studies are consistent in finding that leukemic children younger than 8 years of age have a worse outcome than older ones although both groups perform in the average to bright normal range. It is currently difficult to conclude that such differences in intellectual outcome were caused by the CNS treatment alone or other psychosocial aspects of acquiring leukemia. The confusion present in the literature could be greatly reduced by combining the research efforts on the psychosocial aspects of acquiring leukemia with the studies examining neuropsychological outcome.