A trial looking at radiotherapy after surgery for women over 65 years old with breast cancer (PRIME 2)

Cancer type:

Breast cancer




Phase 3

This trial looked at whether older women with breast cancer need to have radiotherapy after their surgery.

Doctors often treat breast cancer with surgery followed by radiotherapy.

Doctors running this trial felt that there may be no need for older women with breast cancer to have radiotherapy after surgery, especially if they have a small low grade breast cancer and can have hormone therapy. This is because there is less chance that the cancer will come back (recur). All treatments have some side effects and it is important that women do not have treatments they don’t need.

Half of the women in this trial had radiotherapy, and the other half didn’t. Everyone taking part had hormone therapy.

The aim of the trial was to see if it is necessary for older women with low risk breast cancer to have radiotherapy after surgery.

Summary of results

The research team found that breast cancer came back in a few more women who didn’t have radiotherapy.

This trial recruited 1,326 women from 76 hospitals into one of two groups.

  • 658 women in group 1 had radiotherapy after surgery
  • 668 women in group 2 didn’t have radiotherapy after surgery

The trial team analysed the results in 2013 to find out if the cancer had come back in the breast area. This is called local recurrence. They looked at the women who had finished treatment at least 5 years before, and found that the cancer had come back in

  • 5 women (1%) who’d had radiotherapy
  • 26 women (4%) who hadn’t had radiotherapy

They also looked at whether the cancer had spread to another part of the body, and how many women were living 5 years after treatment. They found that there was no difference between the 2 groups.

The research team concluded there was a small increase in the number of cancers that came back in women who didn’t have radiotherapy, but that the rate was very low in both groups. As this didn’t affect how long the women lived, they also concluded that it was safe for this group of women not to have radiotherapy after surgery.

We have based this summary on information from the team who ran the trial.  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. 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 Ian Kunkler
Professor Robin Prescott

Supported by

Chief Scientist Office (CSO)
Experimental Cancer Medicine Centre (ECMC)
Lothian Health Board
NIHR Clinical Research Network: Cancer
Scottish Government
The Breast Cancer Institute
University of Edinburgh

If you have questions about the trial please contact our cancer information nurses

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.

Harriet wanted to try new treatments

Picture of Harriet

“I was keen to go on a clinical trial. I wanted to try new cancer treatments and hopefully help future generations.”

Last reviewed:

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