Download our booklet on screening for ovarian cancer

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Ovacome is a national charity providing support to anyone affected by ovarian cancer. We give information about symptoms, diagnosis, treatments and research. Ovacome runs a telephone and email support line and works to raise awareness and give a voice to all those affected by ovarian cancer.

This booklet is part of a clinical series giving information about ovarian cancer. It is for those who want to know what screening is available, how effective it is and what research is being carried out.

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What is ovarian cancer screening?

Screening is used to try to detect disease before it produces symptoms.

In the UK there are currently screening programmes for breast, cervical and bowel cancer. Before a screening test is made available on the NHS it has to be proved to be accurate, reliable and safe. There are ongoing studies to find a screening test for ovarian cancer. 

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Why is it important to have screening for ovarian cancer?

The early stages of ovarian cancer (stage 1 cancer in one or both of the ovaries) can usually be successfully treated.

Unfortunately, most ovarian cancers are not found at this early stage for a number of reasons:

First of all, ovarian cancer appears more commonly after the menopause (when your periods have stopped). The ovaries are not active at this time, so if they behave abnormally, it is not easy to notice.

Second, the ovaries are deep in the pelvis and are difficult to examine.

Finally, even when you have symptoms, they can be vague and not specific and could be due to a number of other causes.

For these reasons, by the time most people with ovarian cancer develop symptoms and their cancer is found, it has spread outside the ovaries to the pelvis (stage 2), abdomen (stage 3) or beyond the abdomen (stage 4). This makes it far more difficult to treat.

This information suggests that an effective method of screening to find ovarian cancer at an early stage may save the lives of many of those who develop the cancer.

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What screening tests are available?

There are three possible ways of screening for ovarian cancer.

  1. Internal examinations

An internal examination can be performed by a doctor to detect enlarged ovaries. It can detect large ovarian tumours but even experienced doctors are not able to reliably detect ovarian cancer at an early stage. This means that it is not an effective method for detecting early ovarian cancer.

  1. The CA125 blood test

CA125 is a protein in the blood, and is at a high level (over 35 units per millilitre) in most people with ovarian cancer. The CA125 test is often used to check for ovarian cancer in those who have symptoms. It is also used to follow up people during and after treatment for ovarian cancer to detect recurrent disease.

The CA125 test is a quick blood test, which is sent to the laboratory. However, it is only raised in around 50 per cent (50 in 100) of women with early stage ovarian cancer.

A high level of CA125 can also be due to a number of other reasons, such as pregnancy, having a period, fibroids and endometriosis. It is not specific to ovarian cancer.

  1. Ultrasound

Ultrasound scans can be used to look at the size and texture of the ovaries. With ovarian cancer, the ovaries get bigger and the texture becomes abnormal.

Some of these abnormal features are also found in non-cancerous ovarian tumours and other conditions in the pelvis. Ultrasound results can be abnormal even when there is no cancer.

Ultrasound scans can be performed either by placing an ultrasound probe on your abdomen or by putting a probe into your vagina (trans-vaginal scan). Trans-vaginal scans usually give a clearer picture of the ovaries.

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How effective are screening tests?

Several large studies have looked at using either CA125 or ultrasound to screen for ovarian cancer.  They have shown that both tests can detect ovarian cancer before it causes symptoms.

However, it is uncertain whether screening actually saves lives from ovarian cancer. Screening will only be worthwhile if it detects ovarian cancer early enough to make treatment more effective.

Large studies are in progress, and until they have reported their final findings, it is unclear whether screening can save lives or not.

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What problems can ovarian cancer screening involve?

The main problem with screening for ovarian cancer is that the CA125 test and ultrasound scans can be abnormal in people who do not have ovarian cancer. These sorts of results, called false positives, could cause you a great deal of anxiety.  You might need an operation to rule out the possibility of ovarian cancer. Operations can have serious complications, and if no cancer is found, then the operation was unnecessary.

As ovarian cancer is relatively uncommon, it means that more abnormal screening results are due to false positive findings rather than cancer.

Most people find a normal screening result reassuring. However, the CA125 test or ultrasound scan will not pick up every case of ovarian cancer. These sorts of results, called false negatives, do happen. This means a small number of people will be wrongly told that they do not have cancer.

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What have clinical trials shown?

UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS)

This very large randomised, controlled study of ovarian cancer screening was set up in the UK involving 200,000 women aged 50 to 74 years.  The women were screened every year with CA125 testing or ultrasound.  The CA125 tests were looked at to see how they had changed over time.  There was also a control group who are followed up without any screening.

The study reported its preliminary results in 2016. These showed that this form of CA125 testing can detect ovarian cancer at a very early stage and it might be possible to save the lives of some of the women who developed ovarian cancer during the time when they were being screened. However, it did not provide enough evidence to prove whether or not screening would actually save lives.

The UKCTOCS researchers continued to follow up the women on the trial until 2021, but there was still not enough evidence to show that this form of screening will save lives.

UKCTOCS is run by the Gynaecological Cancer Research Centre at University College London and is funded by the Medical Research Council, Cancer Research UK and the National Health Service. You can find details of the trial here.

The UK Familial Ovarian Cancer Screening Study (UKFOCSS)

This was a national study to assess and improve screening in women with a strong family history of ovarian cancer. The study recruited 4000 women at high risk of developing ovarian cancer. These women had a CA125 blood test done every four months and a yearly ultrasound scan.

The UKFOCSS results were published in February 2017. They showed that screening was effective at detecting ovarian cancer before it showed symptoms. Women being screened who were detected as having ovarian cancer were less likely to have advanced cancer.  Their cancers were more likely to be able to be removed completely by surgery, which is known to improve outcomes.

However, screening cannot be seen as a safe alternative to preventative surgery.  This is surgery to remove the fallopian tubes and ovaries, which is offered to women who are at high risk of developing ovarian cancer.

Screening may have a role for women who are not yet ready to have preventative surgery; there are plans to trial this kind of screening as an NHS service to see if it is cost-effective.

You can find more details here.

The Prostate, Lung, Colorectal and Ovarian (PLCO) cancer screening trial

This large US randomised, controlled trial used yearly CA125 tests and ultrasound to screen 39,000 women from the general population for ovarian cancer. 

The trial results were published in 2011 and showed that yearly CA125 tests combined with ultrasound did not save lives and was connected with complications from surgery to remove the ovaries when cancer was suspected.

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Who might benefit from screening?

Women under  50 with no family history

If you are under 50 and have no family history of ovarian cancer or breast cancer, your risk of ovarian cancer is small.

The risk of a false-positive screening result is high. So screening is not recommended if you fall into this group.

Women over  50 with no family history

There is currently no evidence that screening is of value to women in this age group, and there are disadvantages associated with screening. For this reason, routine screening is not currently recommended.

Women with a weak family history

Many women in this group will have one close relative who has developed ovarian cancer and may be anxious about their own risk. If you are in this group your risk is generally only slightly increased and the value of screening is uncertain.

However, your risk may be increased if you have a weak family history and come from an Ashkenazi Jewish family. If you have any doubt about your level of risk, it is sensible to ask your GP and if necessary they can refer you to your local cancer genetics centre for advice and counselling.

Women with a strong family history

Examples include;

  • two or more close relatives have had ovarian cancer or,
  • one relative has had ovarian cancer and another has developed breast cancer aged under 50 or,
  • a relative has developed ovarian cancer and two others have had breast cancer aged under 60.

Having a strong family history may mean that you are at a significantly higher risk of developing ovarian cancer.  Your GP can arrange access to a cancer genetic centre for confirmation of your risk and advice on how you may want to manage it. This may include information on having your ovaries removed as a preventative measure.  

The UKFOCCS study results suggested screening along with on-going discussion about the needs for preventive surgery as an option for high-risk women.

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If you would like more information on the sources and references for this fact sheet, please call us on 0800 008 7054. 

If you would like to discuss anything about ovarian cancer, please phone our supportline on 0800 008 7054 Monday to Friday between 10am and 5pm.

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Reviewed by Dr Jason Yap, Academic Clinical Lecturer in Gynaecological Oncology, Institute of Cancer and Genomic Sciences, University of Birmingham.

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Disclaimer 

Ovacome bookleets provide information and support.  We make every effort to ensure the accuracy and reliability of the information at the time of printing.  The information we give is not a substitute for professional medical care.  If you suspect you have cancer you should consult your doctor as quickly as possible.  Ovacome cannot accept liability for any inaccuracy in linked sources. Rights reserved.

v.3.4

Date last updated May 2021

Date for review October 2022  

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Did you find this fact sheet helpful? We welcome your feedback. If you have any comments or suggestions, please email [email protected] or call 0207 299 6653.