Current National Health Service (NHS) guidelines for breast cancer screening in women under 50 are too restrictive and fail to identify up to 95% of those at higher risk, according to a new study published in the British Journal of Cancer. Researchers warn that the criteria, which primarily focus on inherited genetic mutations, overlook other significant risk factors like lifestyle and reproductive history.

Breast cancer remains a leading cause of death for women under 50 in the UK. While older women are routinely offered mammograms, younger women typically only receive screening if they have a strong family history of the disease. This approach is proving insufficient, as the study found that a significant majority of younger women who develop breast cancer do not have a known family history.

The research, conducted by teams from Cambridge University and the Institute of Cancer Research, utilized a novel risk assessment tool named Boadicea. This calculator incorporates a comprehensive range of factors, including family history, lifestyle choices, reproductive background, and genetic information, to provide a more nuanced risk score. The study's findings suggest that implementing such a tool could identify a substantially larger group of at-risk younger women.

If all women under 50 were assessed using the Boadicea tool, researchers estimate that approximately 26.5% would be classified as having an above-average risk and warrant further investigation. This contrasts sharply with the current NHS guidelines, which would only flag about 1.4% of women in this age group for additional assessment.

A key driver of this disparity is that a significant majority, around 73%, of women under 50 who develop breast cancer within a decade do not have a known family history of the disease. This highlights the limitations of the current Nice guidelines, which heavily rely on family history as the primary determinant for referral.

Lead researcher Dr. Juliet Usher-Smith emphasized the need for the NHS to reconsider its screening criteria in light of these findings. However, she also acknowledged the potential challenges, including increased workloads for healthcare professionals and the possibility of causing unnecessary anxiety and further checks for some women.

Dr. Sowmiya Moorthie from Cancer Research UK, which funded the study, stated that any proposed changes must be accessible and equitable, carefully considering the emotional impact on women who might be referred for additional screening. She also noted that existing risk calculators, including Boadicea, are not infallible.

In response, Nice stated that it welcomed the findings and recognized the potential of multifactorial risk assessment tools. However, the institute maintained that the current evidence does not yet justify a revision of its breast cancer screening guidelines.