# AgeX

Source: https://onco.cc/trials/agex/  
OnCo record `agex` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The largest randomised trial ever run inside a screening programme: nearly four million women cluster-randomised to an extra mammogram below 50 or above 70, and the reason the programme's age range has not moved.

## Summary

AgeX is a nationwide cluster-randomised trial run from the University of Oxford inside the NHS Breast Screening Programme in England, testing whether offering one extra screen at 47 to 49, and one at 71 to 73, reduces breast cancer mortality. Its ISRCTN record gives a target of 4,000,000 participants, recruitment from June 2009 to March 2020 and an end date of December 2031: mortality takes that long to read. NHS England's programme overview still describes the age range as 50 up to the 71st birthday and names AgeX as research, so the trial is the reason the boundary has not moved in either direction. Its predecessor, the UK Age trial, randomised women to annual mammography from 40 and reported in 2020 that the mortality benefit was confined to the first ten years and did not persist.

## Fields

- Kind: Trial
- Status: mixed
- Last checked: 2026-09-25
- Also known as: The AgeX Trial; ISRCTN33292440
- Tags: uk; breast; screening
- Registry id: ISRCTN33292440
- Phase: 3
- Setting: Screening: cluster-randomised offer of one extra screening round at ages 47 to 49 and one at 71 to 73, inside the NHS Breast Screening Programme in England
- Sponsor: University of Oxford
- Enrolled: 4000000
- Result: Recruitment closed March 2020; the mortality endpoint is not due until the trial ends in December 2031 (ISRCTN33292440).

## Sources

- ISRCTN33292440: https://www.isrctn.com/ISRCTN33292440
- UK Age trial final results, Lancet Oncology 2020 (DOI): https://doi.org/10.1016/S1470-2045(20)30398-3
- NHS breast screening programme overview: https://www.gov.uk/guidance/breast-screening-programme-overview

## Connected records

- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/)
- technologies: [Mammography & tomosynthesis](https://onco.cc/technologies/mammography/)

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JSON: https://onco.cc/api/v1/entities/agex.json