{"entity":{"id":"rejuv-agenda-nothing-restores-cognition","kind":"bottleneck","name":"No treatment restores the thinking that cancer treatment takes","aka":[],"tldr":"The memory and concentration problems after chemotherapy and cranial radiotherapy are real and measurable. Every drug tested against them has failed, including one tested properly in 276 people, and nothing restores lost processing speed.","summary":"Two facets of this round reached the same conclusion from different directions. The body facet's record on thinking and memory says there is no drug that speeds recovery, and records that donepezil was tested properly in 276 breast cancer survivors across 87 practices with treatment groups not differing at 24 weeks on any domain. The modafinil result often quoted for cognition came from a secondary analysis inside a fatigue trial, using an open-label run-in and randomised withdrawal of responders, which is not evidence that it treats this. The paediatric facet's record on neurocognitive late effects states the same thing for children in four words: no treatment restores the lost processing speed.\n\nThe measurement problem compounds the treatment problem. Self-reported cognitive difficulty has a consistently absent or weak association with neuropsychological test scores, which does not mean the difficulty is imagined; it means the test measures something else, usually in a quiet room with no competing demands. A field that cannot agree what to measure cannot power a trial on it.\n\nWhat exists is partial. Exercise is mixed and should be described as mixed: a meta-analysis of eleven trials in 890 breast cancer survivors found significant effects on attention, working memory and perceived cognitive ability, while the largest single trial, in 253 survivors, found no difference from a health and wellness comparison on either primary outcome. Cognitive rehabilitation, meaning strategy training rather than restoration, is the approach with the most plausible evidence and has no trial large enough to establish an effect on function. The International Guideline Harmonization Group still lists neurocognitive problems among its guidelines in development, so there is no harmonised surveillance standard after childhood cancer either.\n\nThe third component is the one nobody has separated. After CAR-T cell therapy, no study has disentangled the contribution of the cell therapy itself from the contribution of everything that came before it, which in that population is several lines of chemotherapy, sometimes a transplant, sometimes central nervous system disease and sometimes cranial radiotherapy. The best long-term study has 40 patients and uses self-report rather than formal neuropsychological testing.","asOf":"2026-10-02","links":[{"label":"Management of fatigue in adult survivors of cancer: ASCO and Society for Integrative Oncology guideline update (JCO 2024), which covers the agents also tried for cognition","url":"https://doi.org/10.1200/JCO.24.00541"}],"tags":["rejuvenation","survivorship","open-problem","cognition"],"related":["cognitive-impairment-after-cancer-treatment","rejuv-paed-neurocognitive","rejuv-tx-icans-and-neurocognition","idea-acc-cognitive-rehabilitation-after-chemotherapy","idea-rejuv-core-outcome-set-for-late-effects","rejuv-trial-ex-cipn","rejuvenation-roadmap"],"cancers":[],"sections":["rejuvenation","supportive-care"],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"stage":"biology","severity":"major","metrics":[{"label":"Drugs shown in an adequately sized randomised trial to improve cognition after cancer treatment","value":"None","source":"OnCo body facet, cognitive-impairment-after-cancer-treatment"},{"label":"Donepezil trial: breast cancer survivors randomised, and the result at 24 weeks","value":"276 across 87 practices; treatment groups did not differ on any domain at any timepoint","source":"OnCo body facet, cognitive-impairment-after-cancer-treatment"},{"label":"Largest single randomised trial of exercise for cancer-related cognitive impairment","value":"253 survivors; no difference from health and wellness comparison on either primary outcome","source":"OnCo body facet, cognitive-impairment-after-cancer-treatment"}],"causes":["Self-report and neuropsychological testing measure different things and correlate weakly, so there is no agreed primary endpoint.","The deficits are small on average and large for a minority, which makes an unselected trial underpowered by design.","No mechanism is established well enough to pick a drug target, so candidates have been repurposed on analogy with dementia and stimulant use.","Nobody has separated the contribution of chemotherapy, cranial radiotherapy, cell therapy, anaesthesia, sleep loss, fatigue and depression, and they usually occur together.","There is no commercial sponsor: the condition has no approvable endpoint and the candidate drugs are generic."],"currentEfforts":["Cognitive rehabilitation and strategy training are offered in some centres and are the approach ASCO-adjacent guidance describes as reasonable without an evidence base that supports a recommendation.","Proton therapy is being used in children partly to reduce the dose to healthy brain, though the comparison against photons is across studies rather than within a randomised trial.","The corpus holds a proposal for trials of structured cognitive rehabilitation after chemotherapy and one for exercise and cognitive rehabilitation in older survivors is recruiting."],"successLooksLike":"A core outcome set for cancer-related cognitive impairment that pairs a functional measure with a test, and at least one adequately powered randomised trial of an intervention against it that does not fail for want of an endpoint."},"route":"/bottlenecks/rejuv-agenda-nothing-restores-cognition/","neighbours":{"technology":[{"id":"rejuv-tx-icans-and-neurocognition","kind":"technology","name":"ICANS, and whether thinking recovers after CAR-T","route":"/technologies/rejuv-tx-icans-and-neurocognition/"},{"id":"rejuv-paed-neurocognitive","kind":"technology","name":"Memory, attention and learning after treatment of a childhood cancer","route":"/technologies/rejuv-paed-neurocognitive/"},{"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/"}],"idea":[{"id":"idea-rejuv-core-outcome-set-for-late-effects","kind":"idea","name":"Agree what to measure, so the next systematic review can pool rather than narrate","route":"/ideas/idea-rejuv-core-outcome-set-for-late-effects/"},{"id":"idea-acc-cognitive-rehabilitation-after-chemotherapy","kind":"idea","name":"Trials of structured cognitive rehabilitation for cancer-related cognitive impairment","route":"/ideas/idea-acc-cognitive-rehabilitation-after-chemotherapy/"}],"trial":[{"id":"rejuv-trial-ex-cipn","kind":"trial","name":"EX-CIPN: virtual exercise-based rehabilitation for persistent chemotherapy nerve damage","route":"/trials/rejuv-trial-ex-cipn/"}],"roadmap":[{"id":"rejuvenation-roadmap","kind":"roadmap","name":"Recovery and rejuvenation roadmap: cure is not enough → survivorship gets a name → the cohorts that measured the cost → exercise proven as treatment → biological ageing measured and sold → repair, if anyone funds it","route":"/roadmaps/rejuvenation-roadmap/"}],"section":[{"id":"rejuvenation","kind":"section","name":"Recovery & Rejuvenation","route":"/fronts/rejuvenation/"},{"id":"supportive-care","kind":"section","name":"Supportive Care & Survivorship","route":"/fronts/supportive-care/"}]}}