A trial comparing standard mammograms with a new type of digital mammogram to screen for breast cancer (TOMMY Trial)

Please note - this trial is no longer recruiting patients. We hope to add results when they are available.

Cancer type:

Breast cancer



This trial is comparing 2D mammograms used at the moment in the UK breast screening programme with new 3D mammograms.

Breast screening is recognised to be the best way to find early stage breast cancer, and to reduce the number of deaths from this disease. Doctors use breast X-rays (mammograms) to screen for breast cancer. Current mammograms give 2D pictures of the breast.

But sometimes, it is possible that breast changes may be missed on these mammograms because they are hidden by overlapping normal breast tissue. And, in other cases, healthy tissue that overlaps may look like changes that are a cause for concern. This means women have to come back for further checks, causing unnecessary anxiety.  

This trial is looking at a method called tomosynthesis, which uses digital X-rays and a computer to put together 3D pictures of the breast. We know from early research that tomosynthesis reduces the problem of overlapping tissues. This helps the doctor to see the structures of the breast more clearly. The aim of this trial is to compare the accuracy of tomosynthesis and standard mammograms when diagnosing breast changes found during screening.

Who can enter

You may be able to enter this trial if you are in one of the following situations

  • You are aged between 47 and 73, have had a mammogram as part of routine breast screening, and have been asked to come back for further checks
  • You are aged between 40 and 49 with a family history of breast cancer, and you have been asked to come for yearly mammograms
  • You have been diagnosed with breast cancer in the past, and you are coming for screening

You cannot enter this trial if you

  • Have breast implants
  • Are pregnant

Trial design

This trial will recruit 7,000 women.

When you come for your appointment, you will have the tests already planned as part of your check up, including your mammogram. You will have the trial tomosynthesis straight after your mammogram.

Doctors will then compare the results of the 2 types of breast X-ray.

If tomosynthesis picks up any new information about changes to your breast your doctor will discuss this with you, and arrange for more tests if necessary.

Hospital visits

You will have tomosynthesis at the same appointment as your mammogram. So the trial will add 5 to 10 minutes to your planned hospital appointment.

Side effects

Women find mammograms anything from mildly uncomfortable to painful. Having tomosynthesis is very similar to having a mammogram, so any discomfort you have will be the same.

Taking part in the trial means that you will be exposed to the same amount of radiation as 2 mammograms in a row. The team do not think this will cause any problems to your health.

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

Professor Fiona Gilbert

Supported by

Experimental Cancer Medicine Centre (ECMC)
NIHR Health Technology Assessment (HTA) programme
National Institute for Health Research Cancer Research Network (NCRN)
University of Cambridge

Contact our cancer information nurses for other questions about cancer by:

Phone - 0808 800 4040

Last review date

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

“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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