Cerebral glucose metabolism in survivors of childhood acute lymphoblastic leukemia

BACKGROUND. Cranial radiation therapy (CRT) has been suggested to be a prin cipal factor responsible for long term neurocognitive deficits in survivors of acute lymphoblastic leukemia (ALL). However, neither reduction of the i rradiation dose nor the elimination of irradiation entirely appear to have abolished neurocognitive impairment in long term ALL survivors. Positron em ission tomography (PET) and [F-18] -fluorodeoxyglucose (FDG) can be used to quantitate cerebral glucose metabolism , a potential indicator of treatmen t-induced adverse central nervous system (CNS) effects. The purpose of this study was to assess whether CRT is associated with defects in cerebral glu cose metabolism in long term ALL survivors. The authors also studied whethe r chemotherapy and/or the severity of disease have deleterious effects on g lucose metabolism. METHODS. Ferry long-term survivors of childhood ALL were studied using FDG PET. All subjects went through an elaborate neurocognitive assessment. In 2 0 of these children, the prophylactic treatment of the CNS had been CRT com bined with methotrexate (MTX), and it was MTX only in the remaining 20 chil dren. RESULTS, No major differences were found in the regional cerebral glucose u tilization or in neurocognitive performance between the irradiated and noni rradiated groups. A high leukocyte count at the time of diagnosis was found to be associated inversely with cerebral glucose utilization. CONCLUSIONS. CRT does not appear to affect cerebral glucose metabolism in l ong term survivors of ALL. By contrast, the association between the leukocy te count and glucose utilization implies that disease severity may be partl y responsible for adverse CNS effects in long term survivors of childhood A LL. (C) 2000 American Cancer Society.