Breast Cancer Screening Recommendations — Where Things Stand

In April 2024 the US Preventive Services Task Force lowered its recommended starting age from 50 to 40, advising screening every two years to age 74. Its reasoning was principally that invasive breast cancer incidence among women in their forties has been rising — by roughly 2% a year in the period examined — and that earlier screening particularly benefits Black women, who face worse outcomes.

The UK has not followed, and the reason is a deliberate one: the trade-off at younger ages is finer than it looks. Screening healthy people always carries costs alongside benefits — false alarms leading to further tests and anxiety, and overdiagnosis, meaning treatment for cancers that would never have caused harm. Below 50, denser breast tissue reduces mammographic sensitivity while cancer is less common, which shifts that balance.

Rather than assume, the UK ran the AgeX trial, which between 2009 and 2020 randomised additional invitations to women aged 47–49 and 71–73 to measure the actual effect of extending the range. It is the largest study of its kind and its findings are expected around 2031. Until then, the programme stays at 50 to 71 — a decision to wait for evidence rather than to reject the idea.

This question deserves a straight answer even though it works against our own interests. Dense breast tissue reduces mammographic sensitivity, because dense tissue and cancers both appear white — so it is intuitive that adding ultrasound would help, and adding it does find some additional cancers.

But the USPSTF, reviewing the evidence in 2024, concluded that there is insufficient evidence to judge whether supplemental screening with ultrasound or MRI improves outcomes for women with dense breasts and an otherwise normal mammogram. Additional scanning also generates additional false positives, biopsies and anxiety, and it has not been shown to reduce deaths. That is an honest “we do not yet know”, not a recommendation for it.

So we will not tell you that a private breast ultrasound is an evidence-based addition to normal screening, because that is not what the evidence currently supports. What ultrasound is established for is different and genuinely valuable: investigating a symptom — a lump, a change, pain, discharge — and characterising findings, where it distinguishes a simple cyst from something needing biopsy. Under 40 it is generally the first-line test for a symptom, as our guide to breast ultrasound under 40 explains, and breast density is covered in its own guide.