An already available blood test can better predict ovarian cancer than was previously thought, according to research published in PLOS Medicine yesterday.

The research, funded by Cancer Research UK and NIHR, was led by Dr Garth Funston at the University of Cambridge as part of the CanTest collaborative. It studied over 50,000 women who had a specific type of blood test with their GP in England.

This test is used for women with symptoms that could be caused by ovarian cancer, which are often non-specific. It looks for a protein in the blood called Cancer Antigen 125 (CA125) which can also be a sign of ovarian cancer.

GPs often used this test to help determine if a patient needs referring on for further tests including an ultrasound.

However, the new study found that CA125 was not only raised in women later diagnosed with ovarian cancer, but also that more than 380 women with an abnormal CA125 results instead had another type of cancer such as pancreatic, lung or bowel cancer.

The study also found the proportion of women with an abnormal test who had cancer was much higher in women aged 50 or over (33%) than women younger than 50 years of age (6%).

“This blood test is clearly a useful tool for detecting ovarian cancer in primary care, particularly for women aged 50 or more. Doctors should also consider the possibility of other cancers if the test is abnormal, especially if ovarian cancer has been ruled out, to prevent delays to a diagnosis,” said Dr Walter, senior author of the study from University of Cambridge.

“Our results will help doctors triage women of different ages, selecting those with a higher risk of having cancer for fast referral and further tests. We hope that using the test, in this way, will help diagnose women with cancer earlier, while reducing unnecessary worry in those without the disease,” they added.