Neuropsychological outcome in very young hematopoietic SCT recipients in relation to pretransplant conditioning.

Stem cell transplantation involves conditioning with TBI and/or intensive chemotherapy, which may cause long-term neuropsychological deficits, particularly in children treated at a very young age. The aim of this study was to investigate whether very young children who receive chemotherapy-based conditioning only (BUCY) may have a more favorable neuropsychological outcome than children conditioned with TBI-CY. Twenty-two children who underwent allogeneic SCT at 0.4-3.6 years of age were subject to an extensive neuropsychological assessment at an average of 6.5 years post-therapy. The test results of 10 children exposed to BU were compared to the results of 12 children who had received TBI. Ten of them had received single-dose TBI, whereas two had received fractionated TBI. The BU group performed at age level on verbal measures, but tended to score below age level in the executive and visuo-spatial domains (P<0.01). By comparison, children treated with TBI had more pervasive neuropsychological impairments, including motor deficits (P<0.01) and varying degrees of perceptual (P<0.05), executive and cognitive (P<0.05) problems. In conclusion, children transplanted at a very young age had a more favorable neuropsychological development if conditioned with BUCY than if conditioned with single-dose TBI-CY.