A study looking at ovarian cancer screening for women at high risk - The United Kingdom Familial Ovarian Cancer Screening Study (UK FOCSS)

Part 1
Part 1 of this trial recruited 3,563 women between 2002 and 2008. They had an ultrasound scan and a CA125 blood test once a year. The results showed that 27 women were diagnosed with ovarian cancer within a year of their last screening test, and of these:

• 13 women (48%) were diagnosed with stage 1 or 2 cancer
• 14 women (52%) were diagnosed with stage 3 or 4 cancer

Another 10 women were diagnosed more than a year after their last screening test, and of these:

• 1 woman (10%) was diagnosed with stage 1 cancer
• 9 women (90%) were diagnosed with stage 3 or 4 cancer

The research team found that the gap between screening tests made a difference to the stage of cancer at diagnosis. The results showed that women who had longer than a year between screening tests were more likely to be diagnosed with a more advanced cancer.

The research team thought it may be better to do screening tests more often, so they set up part 2 of the trial in 2007 to try and find out.

Part 2
Part 2 of this trial recruited 4,348 women between 2007 and 2012. This included 2,362 women who had already been in part 1. The women in part 2 had a CA125 blood test every 4 months, and an ultrasound scan once a year.

The CA125 test results were analysed using a computer program, rather than being analysed in the usual way. This is called the Risk of Ovarian Cancer Algorithm (ROCA) and is a more accurate way of using CA125 to detect ovarian cancer.

The results showed that 13 women were diagnosed with cancer because of the results of their screening tests. Of these 13 women:

• 5 women (38%) were diagnosed with stage 1 or 2 cancer
• 8  women (62%) were diagnosed with stage 3 cancer
• no women were diagnosed with stage 4 cancer
• 12 women (92%) had their cancer completely removed with surgery
• 1 woman (8%) had chemotherapy before surgery

Another 6 women were diagnosed less than a year after their last screening test. They were diagnosed because they had an operation to remove their ovaries and fallopian tubes. Of these 6 women:

• 5 women (83%) were diagnosed with stage 1 or 2 cancer
• 1 women (17%) was diagnosed with stage 3 cancer
• no women were diagnosed with stage 4 cancer
• all of the women had their cancer completely removed with surgery

A further 18 women were diagnosed with cancer more than a year after their last screening test as part of this trial. Of these 18 women:

• 1 woman (5%) was diagnosed with stage 1 cancer
• 14 women (78%) were diagnosed with stage 3 cancer
• 3 women (17%) were diagnosed with stage 4 cancer
• 13 women (72%) had their cancer completely removed with surgery
• 7 women (44%) had chemotherapy before surgery

When the trial team analysed the results in 2016, 3 of the 37 women diagnosed with cancer in part 2 of the trial had died. Because this number is so small, they are unable to say for sure if diagnosing ovarian cancer earlier will help women live longer.

The trial team concluded that screening high risk women can pick up ovarian cancer at an earlier stage. But they are not able to say if this would affect how long these women live for.

We have based this summary on information from the research team. The information they sent us has been reviewed by independent specialists (peer reviewed ) and published in a medical journal. The figures we quote above were provided by the trial team who did the research. We have not analysed the data ourselves.