Read the latest HealthWatch newsletter:  Newsletter 116, Summer 2021

Recruitment into the “largest randomised trial of any treatment ever conducted” has been shut down early, and so quietly that it went unnoticed … almost.

The AgeX trial, run by the UK government, had aimed to “assess the risks and benefits” of offering an extra mammogram to women aged 47-49, and additional screening to women between the ages of 70 and 79. But it has been widely criticized by experts and patient groups over its shaky ethics and poor design. Now, without any fanfare, a statement recently appeared on its website: “Following the suspension of routine breast screening in March 2020 due to COVID, and the expected overload on breast screening services when screening eventually re-starts, the AgeX investigators decided in May 2020 that randomization into AgeX should cease permanently.” The statement was spotted by the BMJ and is reported today.(1)

"Other clinical trials have been paused due to COVID, but AgeX has been stopped completely. Could this be because it is a costly and harmful juggernaut of a trial that was conceived and implemented in haste, has grown out of control, and has now become an embarrassment?" says Susan Bewley, HealthWatch's chair, and lead author of a 2019 BMJ Analysis paper that highlighted flaws in AgeX.(2)

By the time recruitment ended, some 4.4 million women had been randomly allocated to the trial. Half will have been sent an extra screening invitation. These mammograms are likely to have resulted in unnecessary surgery for thousands of women who would have been perfectly healthy but for being signed up for the trial.

Unlike regular clinical trials (which should comply with the Helsinki Agreement for the protection of human subjects in research), AgeX was designed without explicit and informed consent, to get maximum participation. HealthWatch has long argued that it will not result in trustworthy data and must be stopped before even more women are harmed.(3) We have called for women in future to be given decision aids clearly explaining the potential risks to help them decide whether to take up screening or not. 

HealthWatch welcomes the ending of recruitment into the AgeX trial. We even agree with the investigators self-penned eulogy that “the establishment of the AgeX trial has been a remarkable achievement”.  But we would still like answers to questions we have been asking for almost a decade including those on the cost and continuing approval that have not been answered by Matt Hancock, nor Jeremy Hunt before him.  Who is responsible for the science of AgeX? Who has overall responsibility for the trial?  How much has it cost the NHS and “the resource-constrained breast screening clinics throughout England”?  

Data on those women who have already been screened will be electronically linked to their health records throughout the 2020s and beyond. But who will be independent enough to be trusted to analyze the data to ensure that any resulting policy decisions will be based on best evidence?


1) Today's BMJ news report by Elisabeth Mahase is at 

2) Our paper on the harms and ethical flaws of AgeX was published in the British Medical Journal 13th April 2019, the full text can be read here:

3) See for yourself. The full story with links to some of the 100+ pages of documents we obtained via freedom of information requests is here:


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