A new screening method that looks at changes in the level of CA125 in the blood can detect twice as many women with ovarian cancer as conventional strategies, suggest results from a giant trial led by researchers at University College London and published in the Journal of Clinical Oncology.

Using a statistical calculation to interpret changing levels in the protein gave a more accurate prediction of individual risk of developing the disease, compared to the conventional screening method which uses a fixed ‘cut-off’ point for CA125, according to data from one arm of the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS), the world’s largest ovarian cancer screening study involving more than 202,000 women.

Researchers detected cancer in 86% of women with invasive epithelial ovarian cancer, whereas the traditional test used in previous trials or in clinical practice would have identified fewer than half of these women (41% or 48%, respectively).

The findings indicate that CA125 “can be an accurate and sensitive screening tool, when used in the context of a woman’s pattern of CA125 over time,” said Ian Jacobs, President of The University of New South Wales, Australia, chief investigator of the trial, and co-inventor of the statistical approach. “What’s normal for one woman may not be so for another. It is the change in levels of this protein that’s important,” he stressed. 

The researchers are hoping that the approach will prove able to pick up ovarian cancer early enough to boost survival rates. Full data from the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS), which should provide some definite evidence on whether the new CA125 method can save lives, are expected later this year.