A study looking at screening the general population for ovarian cancer (UKCTOCS)

Cancer type:

Ovarian cancer





This study looked at whether screening tests would be useful for diagnosing ovarian cancer. It was open to women whose periods had stopped (post menopausal). This trial was supported by Cancer Research UK.


More about this trial

At the moment there is no screening programme for ovarian cancer in the general population. This is because the tests that are used in a screening programme have to be reliable and accurate. Doctors are not sure yet if the tests available at the moment are good enough to pick up ovarian cancers early.

In the UKCTOCS trial, they are comparing 2 screening tests with having no test at all. The women either have a CA 125 blood test or a transvaginal ultrasound scan, or no screening test. The women in the trial have been through the menopause.

The aim of the trial is to see if either of these tests can help doctors diagnose women with ovarian cancer when their cancer is at an early stage. If the tests work well enough it could mean that women with ovarian cancer may be diagnosed earlier, and their cancer treated more effectively.

Summary of results

The results of the very first screening tests showed that both screening tests were useful in picking up signs of ovarian cancer at an early stage. But the CA 125 blood test was slightly more reliable than the transvaginal ultrasound test. Women who had the CA 125 blood test were less likely to need to have the blood test done again. Women who had the transvaginal ultrasound scan sometimes had to have it done a second time to help doctors decide if they needed treatment or not.

More than 200,000 women were recruited. Of those

  • One quarter had a blood test for the CA 125 tumour marker
  • One quarter had a transvaginal ultrasound scan
  • Half had no screening test, doctors call this the ‘control group Open a glossary item

After an average follow up of 11 years 1,282 women were diagnosed with ovarian cancer

  • 338 in the CA 125 group
  • 314 in the transvaginal ultrasound group
  • 630 in the control group

The team compared how many women in each group had died from their ovarian cancer. They found that overall there were fewer deaths in the CA 125 group than in the control group. But it wasn’t a significant difference. The difference could still have been down to chance rather than because of screening.

The study team concluded that further follow up is needed to find out which method of screening is best.

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

Professor Ian Jacobs

Supported by

Cancer Research UK
Department of Health
Medical Research Council (MRC)
National Institute for Health Research Cancer Research Network (NCRN)
Special Trustees of Barts and the London NHS Trust
Special Trustees of University College London Hospital
The Eve Appeal

Other information

This is Cancer Research UK trial number CRUK/03/029.

Questions about cancer? Contact our information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:

Oracle 234

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

Cara took part in a clinical trial

A picture of Cara

"I am glad that taking part in a trial might help others on their own cancer journey.”

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