Screening for ovarian cancer

There is no national screening programme for ovarian cancer in the UK. This is because there isn't a test that reliably picks up ovarian cancer at an early stage. 

What is cancer screening?

Screening means testing people for early stages of a disease. This is before they have any symptoms. For screening to be useful the tests:

• need to be reliable at picking up cancers
• overall must do more good than harm to people taking part
• must be something that people are willing to do

Screening tests are not perfect and have some risks. The screening programme should also be good value for money for the NHS.

Research into tests

There is a lot of research looking into screening for ovarian cancer. Researchers have been looking at 2 main tests:

• the CA125 blood test
• transvaginal ultrasound.

CA125 blood test

CA125 is known as a tumour marker for ovarian cancer. A tumour marker is a chemical given off by cancer cells that circulates in the bloodstream. Women with ovarian cancer tend to have higher levels of CA125 in their blood than women who do not have ovarian cancer. But CA125 can also be raised for other reasons that are not related to cancer. So the test is not completely reliable.

This test would miss some cases of ovarian cancer if it was used on its own. It would also pick out other women who did not have ovarian cancer. They would then need to have further tests, which could cause them anxiety and harm.

We need to have another test that can reliably show who has ovarian cancer and who hasn't. Researchers are looking for other possible tumour markers for ovarian cancer. 

Transvaginal ultrasound

This is an ultrasound examination done by putting an ultrasound probe into the vagina. It gives a better picture of the ovaries than an ultrasound over the tummy (abdomen). Even so, it can still be difficult to tell whether there is a cancer on the ovary or just a harmless cyst.

There is no clear evidence so far that these tests can pick up cancers early and save lives. 

Research trials

A large study called UKCTOCS has looked at whether screening could be useful in ovarian cancer. Over 200,000 women took part in this study. They were between the ages of 50 and 74. 

• Half the group were the control group and didn’t have screening. 
• Around 50,000 had yearly ultrasound scans of their ovaries.
• Around 50,000 had a blood test once a year to measure the levels of CA125 in their blood.

The study started in 2001 and women could join the study until 2005. The researchers followed them up until 2020. The women were followed up for more than 16 years on average. This meant the researchers could find out if either of the screening approaches helped save lives compared to no screening. 

The researchers found that ultrasound tests couldn’t find ovarian cancers earlier or save lives. The blood test did detect cancers earlier, but this didn’t lead to saving lives. The researchers are now looking more closely at the information they collected. This includes doing more tests on the samples they have. 

As a result of this trial, the NHS can’t introduce a national screening programme using these tests. 

What to do if you think you are at risk

You have a higher than average risk of developing ovarian cancer if 2 or more relatives on the same side of your family are diagnosed with ovarian cancer or breast cancer at a young age, particularly under the age of 50.

 Talk to your GP if you think you are at increased risk of ovarian cancer.

They can refer you to your local genetics service, who can assess you and may put you on the UK Familial Ovarian Cancer Registry. You will have counselling about your options, which may include regular tests to try to find ovarian or breast cancer at an early stage. The options may also include surgery to remove the ovaries, reducing your risk of developing ovarian cancer.