A trial looking at using MRI scans to find the stage of rectal cancer (The MERCURY Project)

Cancer type:

Bowel (colorectal) cancer
Rectal cancer





This trial was trying to find out if an MRI scan could tell the stage of cancer of the rectum Open a glossary itembefore surgery.

The stage of your cancer tells doctors how far the cancer has grown and if it has spread. It helps them decide which treatment is best for you. When you have surgery to remove rectal cancer, the surgeon sends the tissue that is removed to the laboratory. A laboratory report, along with other tests, confirms the stage of the cancer.

If MRI scan results can be used to stage the cancer, this could help doctors to work out who would benefit from having radiotherapy before surgery. And who could safely have surgery alone.

The aim of this trial was to see if doctors could use the results of an MRI scan before surgery to work out the stage of rectal cancer. The scan results were compared to the test results (laboratory reports) when the cancer was removed.

Summary of results

The researchers found that having an MRI scan before surgery was a reliable way of working out the stage of rectal cancer.

The trial recruited 408 people who had been diagnosed with rectal cancer. Everybody taking part had an MRI scan. The research team looked at the scans to see if it was likely that a specialist surgeon would be able to remove the cancer with an area of healthy tissue around it (clear margins Open a glossary item).

MRI scans for 349 people suggested that the surgeon should be able to get a clear margin. When they had surgery, laboratory reports showed that 327 of them did have clear margins. So the MRI scan was correct for 94% of these people.

When they published their results, the trial team said that MRI scans can give doctors the information they need to work out who should have radiotherapy before surgery. And who can safely have surgery alone. This stops people having treatment they don’t need.

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

Prof Gina Brown

Supported by

NIHR Clinical Research Network: Cancer
Pelican Cancer Foundation
Wessex Cancer Trust

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Last review date

CRUK internal database number:

Oracle 17

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.”

Last reviewed:

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