Journal of clinical oncology : official journal of the American Society of Clinical Oncology
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Randomized Controlled Trial Comparative Study Clinical Trial
A prospective comparison of neuropsychologic performance of children surviving leukemia who received 18-Gy, 24-Gy, or no cranial irradiation.
To compare the late neuropsychologic toxicities of CNS prophylaxis for childhood acute lymphoblastic leukemia (ALL), longitudinal assessments were performed on three groups of patients: those who received repeated courses of moderate-dose (1 g/m2) intravenous (IV) and intrathecal methotrexate (IT MTX) without cranial irradiation (MTX group, n = 26), those who received IT MTX and 18 Gy cranial irradiation (18-Gy group, n = 23), and those who received IT MTX and 24 Gy cranial irradiation (24-Gy group, n = 28). All patients were free of CNS leukemia at diagnosis and had remained in continuous, complete remission 5 to 11 years (median, 7.4 years) following CNS prophylaxis. An analysis of serial intelligence quotient (IQ), achievement, and neuropsychologic studies revealed no significant influence of either age at CNS prophylaxis or CNS prophylaxis group on any neuropsychologic outcome measure. ⋯ However, comparisons of group means masked declines in individual children; 22% to 30% of children exhibited a clinically significant deterioration (greater than or equal to 15 points) in uncorrected IQ values over the study period. Female sex was associated with an increased risk of deterioration in Verbal IQ, but we were unable to identify risk factors associated with other declines in intellect and achievement. The inability to reliably predict individual patients at risk for clinically significant neuropsychologic toxicities on the basis of age at diagnosis or specific method of CNS prophylaxis suggests that other etiologic factors must be explored as the basis for these changes, such as ecologic factors and chemotherapy during the continuation phase of treatment.