Neuropsychological late effects in young children with medulloblastoma: A longitudinal analysis after 5 and 15 years from the HIT-SKK-'87/'92 studies

Neurooncol Pract. 2025 Oct 1;13(3):597-607. doi: 10.1093/nop/npaf100. eCollection 2026 Jun.

ABSTRACT

BACKGROUND: Young children with medulloblastoma (MB) are especially susceptible for tumor and treatment-related brain damage. Craniospinal irradiation (CSI) has been identified as a main risk factor for cognitive and motor dysfunction 2-5 years after diagnosis. Longitudinal follow-up data on these children beyond 10 years after diagnosis are scarce.

METHODS: To characterize their long-term neurocognitive outcome, we analyzed a cohort of 24 MB patients below the age of 3 years at diagnosis treated within the HIT-SKK'87 (systemic chemotherapy and deferred CSI) and HIT-SKK'92 (systemic chemotherapy and intraventricular methotrexate (MTXi.vt.), no radiotherapy) trials after 5 and 15 years. A comprehensive test battery was used to measure cognitive operations, executive functions with selective attention, and psychomotor abilities.

RESULTS: Overall, MB survivors showed subnormal test results independent of treatment, especially in the domain of motor function. CSI had an additional detrimental effect on general and fluid intelligence and simultaneous processing, whereas MTXi.vt.-recipients never scored worse than irradiated patients. Upon longitudinal follow-up, tests assessing sequential processing and general IQ showed stable or even improved results. In contrast, fluid intelligence, visual-motor integration, and most pronounced tapping speed further declined at 15 years in both the treatment groups and reached the disability zone.

CONCLUSION: Impairment of motor and cognitive skills represents a major handicap for MB survivors. Long-term development of fluid intelligence and visuomotor integration is hindered in all children. CSI further aggravated these dysfunctions. Visual or auditory domains and memory performance are less affected. Long-term neurocognitive support is warranted in young pediatric survivors of MB.

PMID:42131756 | PMC:PMC13161898 | DOI:10.1093/nop/npaf100