The National Institute for Health and Care Excellence (NICE) has recommended new age-based thresholds for cancer antigen 125 (CA125) blood testing that could help GPs identify ovarian cancer earlier in women. 

A draft update to NICE’s guideline on suspected cancer proposes personalised criteria that reflect how ovarian cancer risk changes as women get older. 

Current Testing Limitations

Ovarian cancer affects about 1 in 50 women during their lifetime, with around 7000 diagnoses each year in the UK. The disease is often detected late because symptoms such as bloating, abdominal pain, and early satiety can be vague and overlap with those of other conditions. 

Under current guidance, women are referred for further investigation when their CA125 level reaches 35 IU/mL or above, regardless of age. The CA125 blood test measures protein levels that are often elevated in ovarian cancer and is used to guide further investigation or monitor known disease. 

However, this fixed threshold approach can miss cancers in older women while triggering unnecessary investigations in younger women.

Tailored Testing Approach

The draft guidance recognises that for women under 40, CA125 testing alone lacks sufficient accuracy to guide clinical decisions. For this group, GPs are advised to consider arranging ultrasound scans directly for women with persistent symptoms.

“The committee’s proposed recommendations will ensure more personalised, targeted testing, so women at greatest risk of ovarian cancer are identified and referred sooner,” said Eric Power, deputy director at NICE’s 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 for younger women, freeing up NHS resources.” 

The update also proposes a new age threshold for urgent investigation. Women aged 60 or older with unexplained weight loss of more than 5% over 6 months should receive urgent investigation or suspected cancer pathway referral. 

With prescriptions for hormone replacement therapy rising in England, the guideline also highlights a growing need for clearer evidence on when unexpected bleeding in women taking hormone replacement therapy should prompt investigation for endometrial cancer. The guideline committee has recommended further research to strengthen the evidence base and support clearer clinical decision-making in this area.

Clinical Implementation

NICE guidance is used by GPs and other primary care professionals to determine when patients with potential cancer symptoms should be referred for specialist assessment. 

The suspected cancer guideline covers multiple cancer types and is used to help identify the roughly 143,000 people diagnosed with cancer in England each year. 

Power said the proposed changes “will help improve the detection of cancer and ensure those who need it get swift treatment.”

Public consultation on the draft recommendations is open until Monday 2 February 2026.