A study looking at metformin before surgery for womb cancer (PREMIUM)

Cancer type:

Womb (uterine or endometrial) cancer




Phase 3

This study looked at the diabetes drug metformin for womb cancer and a condition affecting the lining of the womb called endometrial hyperplasia.

More about this trial

This trial was for women with either a type of womb (endometrial) cancer called endometrioid endometrial cancer, or endometrial hyperplasia

Endometrial hyperplasia is a precancerous condition that increases your risk of womb cancer.

Doctors use a drug called metformin to treat diabetes. When this trial was done, laboratory research had shown that metformin may help slow down the growth of some cancers, including womb cancer.

In this study, some women had metformin tablets before their operation, and some women had a placebo (dummy) tablets. 

The research team measured the amount of a protein called Ki-67 in womb cancer cells before and after metformin (or placebo) treatment. Cells produce more Ki-67 when they are growing more quickly. So a drop in the amount of Ki-67 would suggest that the cells are dividing and growing more slowly.  

The main aim of the study was to see if having metformin before surgery helps slow the growth of womb cancer or endometrial hyperplasia.

Summary of results

The research team found that having metformin before surgery for womb cancer did not slow down the growth of the cancer.
This trial was open for people to join between 2015 and 2017. The research team published the results in 2019.
About this trial
88 women with endometrial hyperplasia or a type of womb cancer called endometrioid endometrial cancer joined this trial. 
They were put into 1 of 2 groups at random:
  • 45 had metformin tablets
  • 43 had placebo (dummy) tablets

Everyone taking part had treatment every day for up to 5 weeks. Women in the metformin group had treatment for an average of 21 days. And women in the placebo group had treatment for an average of 22 days. 

They then all had surgery to remove their womb (a hysterectomy).
The research team analysed cells that had been removed during the biopsy women had when they were diagnosed with cancer. They also analysed cells removed during the operation to remove their cancer
They compared the amount of Ki-67 protein in the cells before and after treatment for each woman.
They found that the amount of Ki-67 had dropped a bit for both groups. But it hadn’t dropped any more for the group who had metformin, compared to the group who had the placebo. This suggests the cancer cells of those who had metformin were not growing more slowly.
Side effects
A few more women who had metformin had side effects compared to those who had the placebo. The side effects included feeling or being sick, loss of appetite and diarrhoea. No one taking part stopped treatment because of the side effects they were having.
The research team concluded that having metformin before surgery did not help stop endometrial hyperplasia or endometrioid endometrial cancer growing. They suggest that it’s not a useful treatment for these women. 
But even when a trial shows a treatment isn’t useful for a particular cancer, it adds to our knowledge and understanding of cancer and how to treat it.
Where this information comes from
We have based this summary on information from the research team. The information they sent us has been reviewed by independent specialists (peer reviewed Open a glossary item) and published in a medical journal. The figures we quote above were provided by the trial team who did the research. We have not analysed the data ourselves.

Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Dr Emma Crosbie

Supported by

Central Manchester University Hospital NHS Foundation Trust
NIHR Clinical Research Network: Cancer

Freephone 0808 800 4040

Last review date

CRUK internal database number:


Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Charlie took part in a trial to try new treatments

A picture of Charlie

“I think it’s really important that people keep signing up to these type of trials to push research forward.”

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