New Age-Based Blood Test Thresholds to Catch Ovarian Cancer Earlier

Ovarian cancer affects around one in 50 women during their lifetime, with roughly 7,000 diagnoses each year in the UK. The disease is often detected late because symptoms such as bloating, abdominal pain, and feeling full quickly are vague and overlap with many non-cancerous conditions. A new draft guidance now aims to refine how ovarian cancer risk is assessed in primary care by aligning blood test thresholds more closely with age-related risk.

The draft update, proposed by the National Institute for Health and Care Excellence (NICE, London, UK), focuses on revising how the CA125 blood test is used when ovarian cancer is suspected. CA125 measures a protein that is often elevated in ovarian cancer and is commonly used to guide further investigation or monitor known disease.

Image: The draft guideline proposes age-adjusted CA125 thresholds for ovarian cancer detection (Photo courtesy of Adobe Stock)

Under current guidance, women are referred for further investigation if their CA125 level is 35 IU/ml or above, regardless of age. Evidence reviewed by the guideline committee shows that this fixed threshold may miss cancers in older women while prompting unnecessary referrals in younger women. The draft guidance, therefore, proposes age-specific thresholds that better reflect how ovarian cancer risk changes across the lifespan.

The update recognizes that CA125 testing alone is not sufficiently accurate in women under 40 years of age. For this group, GPs are advised to consider arranging an ultrasound scan directly when symptoms persist. The guideline also proposes urgent investigation or referral for people aged 60 and over who experience unexplained weight loss of more than 5% over six months. The draft guidance also highlights gaps in evidence related to unexpected bleeding in women taking hormone replacement therapy, particularly as HRT prescribing continues to rise in England.

NICE has recommended further research to clarify when such symptoms should trigger investigation for endometrial cancer. Together, these changes aim to support earlier cancer detection while reducing unnecessary testing and anxiety for lower-risk patients. The NICE guideline committee has noted that updating referral thresholds and identifying evidence gaps will help primary care professionals make more informed decisions and improve cancer detection pathways across multiple cancer types.

“The committee’s proposed recommendations will ensure more personalized, targeted testing, so women at greatest risk of ovarian cancer are identified and referred sooner,” said Eric Power, deputy director, Centre for Guidelines. “This tailored approach will mean GPs can make more informed decisions about which patients need urgent investigation, while reducing unnecessary ultrasound scans, freeing up NHS resources. These updates will ensure that our guideline reflects the latest evidence and will help improve the detection of cancer and ensure those who need it get swift treatment.”

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