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

Purpose: To test the hypothesis that inadequate development of normal-appearing white matter (NAWM) is associated with the relationship between young age at the time of craniospinal irradiation (CRT) and deficient neurocognitive 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. Neurocognitive evaluations were conducted with tests of intellect (intelligent quotient; IQ), verbal memory, and sustained attention. Quantitative magnetic resonance 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 with worse performance on all neurocognitive tests except that of verbal memory. An increased time from completion of CRT was significantly associated with 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. These analyses revealed that MAWM accounted for a significant amount of the association between age at CRT and IQ, factual knowledge, and verbal and nonverbal thinking, but not sustained attention or verbal memory. Conclusion: The present results suggest that, at least for some cognitive functions, deficient development and/or loss of NAWM after CRT may provide a neuroanatomical substrate for the adverse impact of a young age at the time of CRT. J Clin Oncol 19:472-479. (C) 2001 by American Society of Clinical Oncology.