High-dose chemotherapy (HDC) strategies were developed in brain tumor protocols for young children to prevent neuropsychological (NP) impairments associated with radiotherapy. However, comprehensive NP evaluations of these children treated with such strategies remain limited. We examined the long-term neurocognitive outcomes of young children (<6 years) with medulloblastoma, treated similarly, with a HDC strategy "according to" the chemotherapy regimen of the protocol CCG 99703. This retrospective study included young children less than 6 years of age at diagnosis of medulloblastoma treated from 1998 to 2011 at 7 North American institutions. Twenty-four patients who had at least one NP assessment post-treatment are the focus of the current study. Of 24 patients in this review, 15 (63%) were male and the mean age at diagnosis was 29.4 months (SD = 13.5). Posterior fossa syndrome (PFs) was reported in five patients (21%). Nine (37.5%) received radiotherapy (5 focal, 4 craniospinal). On average, children were assessed 3.5 years (SD = 1.8) post-diagnosis, and full-scale intellectual quotient (FSIQ) scores ranged from 56 to 119 ([Formula: see text]= 92; SD = 16.8). The majority of children (74%) had low-average to average NP functioning. Very young children treated with radiotherapy, who needed hearing support or with PFs had worse neurocognitive outcomes. Clinically significant deficits (<10th percentile) in at least one area of NP functioning were found in 25% of the children. NP data obtained from this sample of survivors of medulloblastoma in early childhood, all treated with sequential HDC and 1/3 with radiotherapy, describe NP functioning within average normal limits overall. However, almost 25% of children had significant deficits in specific domains.
Keywords: High-dose chemotherapy; Medulloblastoma; Neurocognitive outcome; Radiation avoidance; Young children.