Is breast cancer screening worth it?

Mammography screening reduces breast cancer mortality. European guidelines assume a reduction of at least 20% over thirty years. An overview of 28 systematic reviews shows estimates ranging from a 49% reduction in mortality to virtually no effect, depending on how the study was designed. Most of the underlying reviews carry a high risk of bias, so the precise magnitude is uncertain. But the trend is clear: participation helps¹,²,³,⁴.

Set against that benefit are two serious drawbacks. First, false-positive results: an alarm that turns out to be unfounded, but still causes anxiety and leads to further investigation. Second, overdiagnosis: a tumour that would never have caused symptoms, yet is treated anyway. These are recognised limitations of the current programme, in which every woman receives the same invitation regardless of her personal risk.

In women aged 70 and older the balance is less favourable. In the 70-to-74 age group, approximately 31% of cancers found through screening may involve overdiagnosis. In women aged 75 to 84 that figure rises to 47%, and above the age of 85 to well over half. In those same groups no measurable reduction in mortality was found. The study has methodological limitations, but the message is clear: above the age of 75, weighing the pros and cons deserves a separate conversation with your doctor⁵.

Women with dense breast tissue may benefit from additional MRI after a negative mammogram. This yielded an average of 1.52 extra cancers detected per 1,000 screening rounds, significantly more than ultrasound or tomosynthesis. MRI is not a replacement for regular screening, but a targeted supplement for women with a high risk or extremely dense breast tissue⁶.

The future probably lies with personalised screening using AI. A randomised study showed that an AI model could select the 6.9% of women with the highest risk after a negative mammogram for additional MRI. This yielded nearly four times more cancers detected per MRI performed compared with selection based on breast density alone⁷. A calculation for the British screening programme showed that AI-driven personalisation is expected to produce both health gains and cost savings⁸. These are still modelling calculations, however; real-world research must confirm this.