Risks of young age for selected neurocognitive deficits in medulloblastomaare associated with white matter loss

Purpose: To test the hypothesis that inadequate development of normal-appea ring white matter (NAWM) is associated with the relationship between young age at the time of craniospinal irradiation (CRT) and deficient neurocognit ive performance in survivors of childhood medulloblastoma. Patients and Methods: Forty-two patients treated since 1985 participated in this cross-sectional study. All had been treated with CRT with or without chemotherapy and had survived 1 or more years after treatment. Neurocogniti ve evaluations were conducted with tests of intellect (intelligent quotient ; IQ), verbal memory, and sustained attention. Quantitative magnetic resona nce imaging, using ct hybrid neural network, assessed the volume of NAWM. Results: Neurocognitive test results were below normal expectations for age at the time of testing. A young age at CRT was significantly associated wi th worse performance on all neurocognitive tests except that of verbal memo ry. An increased time from completion of CRT was significantly associated w ith worse performance on all neurocognitive tests except that of sustained attention, After statistically controlling for the effects of rime from CRT , we examined the association of NAWM with neurocognitive test results. The se analyses revealed that MAWM accounted for a significant amount of the as sociation between age at CRT and IQ, factual knowledge, and verbal and nonv erbal thinking, but not sustained attention or verbal memory. Conclusion: The present results suggest that, at least for some cognitive f unctions, deficient development and/or loss of NAWM after CRT may provide a neuroanatomical substrate for the adverse impact of a young age at the tim e of CRT. J Clin Oncol 19:472-479. (C) 2001 by American Society of Clinical Oncology.