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s survival rates for the most prevalent types of childhood cancer have dramatically improved over the past three decades, the concept of "cure" has evolved to include optimizing the quality of life among survivors. Although significant progress has been made in addressing some adverse late effects of treatment that limit quality of life, such as endocrinopathies, other late effects remain problematic. This article will review neurocognitive late effects as defined by problems with thinking, learning, and remembering among survivors of childhood cancer. After defining the neurocognitive phenotype that characterizes many such children, we will review the etiology and risk factors for damage to the central nervous system associated with childhood cancer and its treatment. We will then discuss methods of pharmacologic, behavioral, and ecological intervention that may help reduce learning problems among surviving children. Finally, we will identify areas of future research that will be critical to the elimination of neurocognitive late effects in childhood cancer survivors and the resources needed to implement such research.
For children diagnosed with cancer in the early 1970s, the probabilities were approximately the same as to whether they would be cured or succumb to their illness. For children diagnosed in the early 1990s, the overall prognosis for survival had increased to 75%, with some types of cancer exceeding 80% cure rates. 1 With improvement in survival, clinicians became more aware of late-occurring adverse effects of treatment for childhood cancer. Neurocognitive late effects, defined by problems with thinking, learning, and remembering, have become an expanding area of scientific interest, especially for the two most frequent types of childhood cancer, acute lymphoblastic leukemia (ALL) and brain tumors.
Although estimates vary according to patient diagnosis and age, aggressiveness of therapy, and length of follow-up, most researchers would agree that the incidence of neurocognitive late effects is unaccept-