# Agree what to measure, so the next systematic review can pool rather than narrate

Source: https://onco.cc/ideas/idea-rejuv-core-outcome-set-for-late-effects/  
OnCo record `idea-rejuv-core-outcome-set-for-late-effects` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A reported prevalence of 0 to 84 per cent for the same late effect is a measurement failure. Core outcome sets are cheap, need no new biology, and would unlock the studies the field has already paid for.

## Summary

This is the least glamorous and probably the highest-return item on this agenda. Across this front, studies exist and cannot be combined: kidney impairment after childhood cancer is reported between 0 and 84 per cent with no agreed outcome measure; nail changes after chemotherapy between 0 and 44 per cent; time to diagnosis in adolescents and young adults could not be meta-analysed at all because the distributions were incomparable; quality of life after a stoma or limb loss was measured inconsistently with scores varying substantially; fear of recurrence, the most reported unmet need in survivorship, still lacks consensus definitions and well-validated measures by its own field's assessment.

A core outcome set specifies a minimum set of outcomes and the instrument for each, agreed by a structured consensus process including patients. It does not stop anyone measuring more. It costs a fraction of a single trial, and it changes what a decade of subsequent studies can be used for. The methodology is established in other fields and has been applied in oncology for specific tumour types.

The lever is not persuasion but funding and publication. A funder that requires the relevant core outcome set in any survivorship application, and a journal that requires it to be reported, changes practice faster than consensus alone.

## Fields

- Kind: Idea
- Last checked: 2026-10-02
- Tags: rejuvenation; survivorship; open-problem; outcomes; methods
- Hypothesis: Agreed core outcome sets for the principal late effects, with named instruments, would make the existing and future literature poolable and remove the commonest reason this field cannot state a number.
- Rationale: At least seven records written in this round state a named gap where a prevalence should be, each because the underlying studies used incompatible measures. The cost of fixing that is a consensus process per outcome; the cost of not fixing it is that every systematic review in this field narrates instead of pooling and every trial argues about its endpoint from first principles.
- Proposed test: Run structured consensus processes, with survivors in the panel, for the highest-volume late effects: cognition, fatigue, kidney function, sexual function, lymphoedema, fear of recurrence and bowel function after pelvic radiotherapy. Then have a major funder require the relevant set in survivorship applications, and measure uptake in published studies three and five years later.
- Maturity: speculative
- Actor: research

## Sources

- Hudson et al., Clinical ascertainment of health outcomes among adults treated for childhood cancer (JAMA 2013;309:2371): https://doi.org/10.1001/jama.2013.6296

## Connected records

- technologies: [Fear that the cancer will come back: how common it is, and when it stops being ordinary worry](https://onco.cc/technologies/rejuv-mind-fear-of-recurrence/), [How long it takes to diagnose cancer in a young person, and what the evidence actually says](https://onco.cc/technologies/rejuv-ayac-diagnostic-delay/), [Kidneys after cisplatin, ifosfamide, radiotherapy and nephrectomy in childhood](https://onco.cc/technologies/rejuv-paed-kidneys/), [Thinking and memory after cancer treatment: what is measurable, and what helps](https://onco.cc/technologies/cognitive-impairment-after-cancer-treatment/)
- ideas: [Give survivorship interventions a shared control arm](https://onco.cc/ideas/idea-rejuv-survivorship-platform-trial/), [Patient-reported side-effects (PRO-CTCAE) collected and published in every registrational trial](https://onco.cc/ideas/idea-moon-pro-ctcae-in-every-pivotal-trial/)
- collections: [International Guideline Harmonization Group for late effects of childhood cancer](https://onco.cc/collections/ighg/)
- roadmaps: [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](https://onco.cc/roadmaps/rejuvenation-roadmap/)
- fronts: [Recovery & Rejuvenation](https://onco.cc/fronts/rejuvenation/), [Supportive Care & Survivorship](https://onco.cc/fronts/supportive-care/)
- bottlenecks: [No treatment restores the thinking that cancer treatment takes](https://onco.cc/bottlenecks/rejuv-agenda-nothing-restores-cognition/), [Preclinical results do not reproduce](https://onco.cc/bottlenecks/b-reproducibility/), [The field cannot pool its own studies, because it has not agreed what to measure](https://onco.cc/bottlenecks/rejuv-agenda-no-agreed-outcome-measures/), [Toxicity and quality of life are undervalued](https://onco.cc/bottlenecks/b-toxicity-qol/)

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