Objective To investigate the long-term cognitive consequences of malignant pediatric brain tumor and its treatment, and factors explaining variability in cognitive functioning among survivors. Method: A geographical cohort of survivors of pediatric medulloblastoma (MB) and supratentorial primitive neuroectodermal tumor (CNS-PNET), treated between 1974 and 2013, was invited to participate. Of the 63 surviving patients, 50 (79%) consented to participation. The participants were tested with a battery of neuropsychological tests covering a wide age range. Verbal cognition, nonverbal cognition, processing speed, attention, memory, executive functioning, and manual dexterity were assessed. The participants were between 5:5 and 51:11 years of age at time of assessment. Assessments took place on average 19 years after primary tumor resective surgery. Results: One participant had a severe intellectual disability. For the rest, IQ varied from 52 to 125, with a mean score of 88.0 (SD 19.7). Twenty-eight (56%) of the participants had full-scale IQ scores in the age-average range or above. Gender, age at operation, time since operation, the presence of secondary medical complications, and treatment variables explained 46% of the variability in IQ scores, F(4,44) = 9.5, p<.001. The presence of endocrine insufficiency in combination with either epilepsy and/or hydrocephalus was associated with lowered IQ, lowered processing speed, and memory impairments. Conclusion: Patients treated for childhood MB and CNS-PNET have a lifelong risk of medical sequelae, including impaired cognitive functioning. This study adds to the literature by demonstrating the importance of following neuropsychological functioning closely, especially processing speed, learning, and memory, in survivors who have multiple secondary medical complications.
Keywords: Pediatric brain tumor; cognition; endocrine insufficiency; medulloblastoma; radiation therapy.