{"entity":{"id":"rejuv-paed-neurocognitive","kind":"technology","name":"Memory, attention and learning after treatment of a childhood cancer","aka":[],"tldr":"The commonest pattern after cranial radiotherapy in a young child is not forgetting what was learned but learning more slowly than other children, so the gap widens with every year at school. In 44 children treated for medulloblastoma the measured loss was 2.55 IQ points a year, and raw scores were still rising: they were gaining skills, just more slowly than the test expected for their age.","summary":"The most important thing to understand about neurocognitive late effects in children is the shape of them, which was settled by a longitudinal study of 44 children treated for medulloblastoma with 150 examinations between them. Mean estimated full-scale IQ at the most recent examination was 83.57, more than one standard deviation below population norms, and performance fell by a mean of 2.55 estimated IQ points per year. But the raw subtest scores rose over time. The authors' conclusion is the sentence to give a parent: the results support \"the hypothesis that MB patients demonstrate a decline in IQ values because of an inability to acquire new skills and information at a rate comparable to their healthy same-age peers, as opposed to a loss of previously acquired information and skills\". A child is not losing what they had. They are falling behind a moving target, which is why the problem looks worse each year and why school support matters more than anything given in clinic.\n\nDose and age at treatment are the two determinants. In 111 children treated for medulloblastoma with risk-adapted craniospinal irradiation, high-risk patients receiving 36 to 39.6 gray and average-risk patients 23.4 gray, the whole group declined significantly: IQ by 1.59 points a year (P = .006), reading by 2.95 (P < .0001), spelling by 2.94 (P < .0001) and mathematics by 1.87 (P = .003). The effects on IQ, reading and spelling were moderated by age, with the greatest rates of decline in high-risk patients under seven at diagnosis, and the conclusion was that \"Young age at diagnosis was the most prominent risk factor for neurocognitive deficits among survivors of MB despite reductions in CSI dosing and efforts to limit the boost volume\". An imaging study in 42 medulloblastoma survivors found that the volume of normal-appearing white matter accounted for a significant part of the association between young age at irradiation and IQ, factual knowledge and verbal and non-verbal thinking, which is the mechanism: radiotherapy interferes with myelination that is still happening.\n\nChemotherapy alone is not neutral. In the St Jude Lifetime Cohort study of 567 adult survivors of childhood acute lymphoblastic leukaemia, mean age 33, mean 26 years from diagnosis, impairment rates across domains ranged from 28.6 to 58.9 per cent, and survivors treated with chemotherapy only showed increased impairment in all domains (all P values below .006). Among those who had no cranial radiotherapy, dexamethasone was associated with impaired attention (relative risk 2.12, 95 per cent confidence interval 1.11 to 4.03) and executive function (2.42, 1.20 to 4.91). Risk of executive function problems increased with time since treatment in a dose-dependent relationship with cranial radiotherapy, and impairment was associated with lower educational attainment and unemployment.\n\nProton therapy is the main attempt to reduce the exposure. In a single-arm phase 2 study of 59 children with medulloblastoma treated with proton craniospinal irradiation, full-scale IQ fell by 1.5 points a year (0.9 to 2.1) over a median 5.2 years, driven by processing speed and verbal comprehension, while perceptual reasoning and working memory did not change significantly, with 3-year progression-free survival of 83 per cent. That is a smaller annual decline than the photon series above, but the comparison is across studies rather than within a randomised trial, so it should not be read as a measured benefit.\n\nWhat comes back, and when: the deficit does not reverse, and expecting it to is the commonest source of disappointment. What changes the outcome is the school: in the Childhood Cancer Survivor Study, 23 per cent of survivors used special education services against 8 per cent of siblings, with the greatest difference in those diagnosed before age 6, and survivors of leukaemia, central nervous system tumours, non-Hodgkin lymphoma and neuroblastoma were significantly less likely than siblings to finish high school, but \"when survivors received SE services, risk estimates approximated those of the sibling SE population\". The service closed the gap. The International Guideline Harmonization Group lists neurocognitive problems among its guidelines still in development, so there is no harmonised surveillance standard yet.","status":"established","asOf":"2026-10-02","wikipedia":"https://en.wikipedia.org/wiki/Neurocognitive_disorder","links":[{"label":"Patterns of intellectual development among survivors of paediatric medulloblastoma: a longitudinal analysis (JCO 2001)","url":"https://doi.org/10.1200/JCO.2001.19.8.2302"},{"label":"Neurocognitive consequences of risk-adapted therapy for childhood medulloblastoma (JCO 2005)","url":"https://doi.org/10.1200/JCO.2005.00.703"},{"label":"Risks of young age for selected neurocognitive deficits in medulloblastoma are associated with white matter loss (JCO 2001)","url":"https://doi.org/10.1200/JCO.2001.19.2.472"},{"label":"Neurocognitive outcomes decades after treatment for childhood acute lymphoblastic leukaemia (SJLIFE) (JCO 2013)","url":"https://doi.org/10.1200/JCO.2012.48.2315"},{"label":"Long-term toxic effects of proton radiotherapy for paediatric medulloblastoma: a phase 2 single-arm study (Lancet Oncol 2016)","url":"https://doi.org/10.1016/S1470-2045(15)00167-9"},{"label":"Utilization of special education services and educational attainment among long-term survivors of childhood cancer (CCSS) (Cancer 2003)","url":"https://doi.org/10.1002/cncr.11117"}],"tags":["rejuvenation","survivorship","paediatric","late-effects","evidence:moderate"],"related":["sjlife","ccss","ighg"],"cancers":["childhood-cancers","medulloblastoma","all-leukemia","paediatric-low-grade-glioma","paediatric-high-grade-glioma","aml-paediatric"],"sections":["rejuvenation","supportive-care"],"technologies":["cognitive-impairment-after-cancer-treatment","proton-therapy","radiotherapy","rejuv-paed-hearing","rejuv-ayac-education-and-work","rejuv-paed-cog-ltfu-guidelines"],"targets":[],"drugs":["methotrexate","dexamethasone"],"companies":[],"institutions":[],"pathways":[],"terms":["late-effects","quality-of-life"],"trials":[],"people":[],"bottlenecks":["b-survivorship","b-toxicity-qol"],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"principle":"Cranial irradiation and intrathecal chemotherapy injure oligodendrocyte precursors and the hippocampal neural stem cell niche during the years in which white matter is still being laid down. The result is reduced volume and integrity of normal-appearing white matter, which slows processing speed and working memory, the substrates on which new learning depends. The deficit therefore presents as a reduced rate of acquisition rather than as amnesia, and widens as the age-expected norm rises.","strengths":["The pattern is well characterised, so it can be explained honestly to a family","Special education services measurably closed the gap in educational attainment","Dose and volume reduction and proton therapy address the exposure directly"],"limitations":["No treatment restores the lost processing speed","The proton comparison is across studies, not randomised","No harmonised international surveillance guideline for neurocognitive late effects yet"]},"route":"/technologies/rejuv-paed-neurocognitive/","neighbours":{"collection":[{"id":"ighg","kind":"collection","name":"International Guideline Harmonization Group for late effects of childhood cancer","route":"/collections/ighg/"},{"id":"sjlife","kind":"collection","name":"St Jude Lifetime Cohort Study (SJLIFE)","route":"/collections/sjlife/"}],"trial":[{"id":"ccss","kind":"trial","name":"Childhood Cancer Survivor Study (CCSS)","route":"/trials/ccss/"}],"cancer":[{"id":"all-leukemia","kind":"cancer","name":"Acute lymphoblastic leukaemia","route":"/cancers/all-leukemia/"},{"id":"aml-paediatric","kind":"cancer","name":"Acute myeloid leukaemia in children","route":"/cancers/aml-paediatric/"},{"id":"childhood-cancers","kind":"cancer","name":"Childhood cancers (all types)","route":"/cancers/childhood-cancers/"},{"id":"medulloblastoma","kind":"cancer","name":"Medulloblastoma","route":"/cancers/medulloblastoma/"},{"id":"paediatric-high-grade-glioma","kind":"cancer","name":"Paediatric high-grade glioma (excluding diffuse midline glioma)","route":"/cancers/paediatric-high-grade-glioma/"},{"id":"paediatric-low-grade-glioma","kind":"cancer","name":"Paediatric low-grade glioma","route":"/cancers/paediatric-low-grade-glioma/"}],"section":[{"id":"rejuvenation","kind":"section","name":"Recovery & Rejuvenation","route":"/fronts/rejuvenation/"},{"id":"supportive-care","kind":"section","name":"Supportive Care & Survivorship","route":"/fronts/supportive-care/"}],"technology":[{"id":"rejuv-ayac-education-and-work","kind":"technology","name":"Education, work and the years that were interrupted","route":"/technologies/rejuv-ayac-education-and-work/"},{"id":"rejuv-paed-hearing","kind":"technology","name":"Hearing after platinum and cranial radiotherapy in a developing child","route":"/technologies/rejuv-paed-hearing/"},{"id":"rejuv-paed-chronic-disease-burden","kind":"technology","name":"How much illness childhood cancer survivors carry, and at what age","route":"/technologies/rejuv-paed-chronic-disease-burden/"},{"id":"rejuv-measure-cognitive-function","kind":"technology","name":"Measuring memory and concentration after treatment","route":"/technologies/rejuv-measure-cognitive-function/"},{"id":"proton-therapy","kind":"technology","name":"Proton therapy","route":"/technologies/proton-therapy/"},{"id":"rejuv-paed-cog-ltfu-guidelines","kind":"technology","name":"The Children's Oncology Group Long-Term Follow-Up Guidelines","route":"/technologies/rejuv-paed-cog-ltfu-guidelines/"},{"id":"cognitive-impairment-after-cancer-treatment","kind":"technology","name":"Thinking and memory after cancer treatment: what is measurable, and what helps","route":"/technologies/cognitive-impairment-after-cancer-treatment/"}],"term":[{"id":"late-effects","kind":"term","name":"Late effects and survivorship toxicity","route":"/terms/late-effects/"},{"id":"quality-of-life","kind":"term","name":"Quality of life","route":"/terms/quality-of-life/"},{"id":"radiotherapy","kind":"term","name":"Radiotherapy","route":"/terms/radiotherapy/"}],"drug":[{"id":"dexamethasone","kind":"drug","name":"Dexamethasone","route":"/drugs/dexamethasone/"},{"id":"methotrexate","kind":"drug","name":"Methotrexate","route":"/drugs/methotrexate/"}],"bottleneck":[{"id":"rejuv-agenda-nothing-restores-cognition","kind":"bottleneck","name":"No treatment restores the thinking that cancer treatment takes","route":"/bottlenecks/rejuv-agenda-nothing-restores-cognition/"},{"id":"b-survivorship","kind":"bottleneck","name":"Survivorship and late effects are neglected","route":"/bottlenecks/b-survivorship/"},{"id":"b-toxicity-qol","kind":"bottleneck","name":"Toxicity and quality of life are undervalued","route":"/bottlenecks/b-toxicity-qol/"}]}}