Breast Cancer Screening Now Starts at 40: What the 2024 USPSTF Update Means

What changed on 30 April 2024

The US Preventive Services Task Force issued a final recommendation: biennial screening mammography for women aged 40 to 74. Biennial means every two years. The grade is B, meaning moderate certainty of a moderate net benefit.

The old guidance started routine screening at 50, leaving the forties to individual choice. Moving the start a decade earlier is the change everyone reported.

Two other parts of the same statement got far less coverage.

For women 75 or older, the task force issued an I statement. The current evidence is insufficient to weigh benefits against harms in that group.

For women with dense breasts it issued another I statement, on adding ultrasound or MRI after an otherwise negative mammogram. Insufficient evidence, again.

Who the recommendation covers

The task force is specific. It applies to cisgender women and all others assigned female at birth, including transgender men and nonbinary people, aged 40 or older, at average risk. It also applies to women with factors linked to higher risk, such as a family history of breast cancer.

Higher risk still shifts the plan in practice. NCI notes that someone treated for a childhood cancer with radiation to the breast or chest may be advised to start at 25, or eight years after finishing radiation, whichever comes later. People with harmful BRCA1 or BRCA2 mutations may also start earlier or screen more often.

What a mammogram is and what it shows

A mammogram is an x-ray image of the breast. The same machines do screening and diagnostic mammograms. A diagnostic one takes more angles, so the radiation dose is higher.

NCI lists what the images can reveal: a mass, calcium deposits called calcifications, other changes, and breast density.

The shape of a mass matters. A benign lump often looks smooth and round with clear edges, usually a cyst. A jagged outline or odd shape prompts more tests.

Calcifications come in two kinds, and neither has anything to do with calcium in food. Macrocalcifications look like small white dots and are usually benign, often from aging, an old injury or inflammation. Microcalcifications look like white specks. Clustered a certain way, they can signal ductal carcinoma in situ or breast cancer.

What the result letter means

Results usually arrive within about two weeks. NCI says to contact your provider if they do not.

The report carries a BI-RADS category, a standard scale radiologists use.

• 0 means more imaging is needed before a category can be assigned.
• 1 is negative. Continue regular screening.
• 2 is a benign finding. Continue regular screening.
• 3 is probably benign, with a six-month follow-up mammogram.
• 4 is a suspicious abnormality, which may require a biopsy.
• 5 is highly suggestive of cancer and requires a biopsy.
• 6 means cancer already confirmed by biopsy.

Most people called back are not found to have breast cancer. Our page on what a mammogram callback means covers what usually happens next.

The harms, named plainly

The task force lists them. False-positive results, which bring psychological harm, extra testing and invasive follow-up. Overdiagnosis and overtreatment of lesions that would never have caused health problems. And radiation exposure.

Overdiagnosis is the hardest to feel. It means finding, and treating, a cancer that would have sat there harmlessly for life. Nobody can tell at the time which one that is.

Screening a decade earlier means more screening overall. That raises both the cancers found and these costs.

Breast density adds a wrinkle. NCI says mammography is more likely to miss cancer in women with dense breasts. From September 2024 the FDA requires centers to tell patients their breast density, explain that dense tissue raises risk and hides cancer, and note that other imaging may help. What that other imaging should be is exactly what the task force said it cannot yet judge. Our page on breast density covers the options.

When to get checked

Screening is for people without symptoms. Symptoms have their own route, and it is faster.

Book an appointment for a new lump in the breast or armpit, a change in breast size or shape, skin dimpling, nipple discharge that is not milk, a nipple turning inward, or lasting redness or scaling. Do that whatever the screening schedule says. A diagnostic mammogram, not a screening one, is the test that follows.

For screening itself the numbers are simple. Start at 40, repeat every two years, continue to 74, if you are at average risk. The American Cancer Society welcomed the 2024 change and offers annual screening from 40 in its own guidance. Our page on mammograms explains what the appointment involves.

Practical detail from NCI: avoid deodorants, powders, lotions and creams on the breasts or underarms that day, and try not to book right before or during a period, when breasts are tender.

The numbers behind the decision

The task force notes that breast cancer is the second most common cancer among US women, and the second most common cause of their cancer deaths. An estimated 43,170 women died of it in 2023.

The American Cancer Society projects 321,910 new US female breast cancer cases and 42,140 deaths for 2026, and SEER reprints that projection. NCI's own registry data put the median age at diagnosis at 64.

Five-year relative survival for 2016 to 2022 cases is 91.9 percent overall. By spread at diagnosis it is 100.0 percent while confined to the breast, 87.5 percent with regional lymph nodes involved, and 33.8 percent for distant disease. Sixty-four percent are found localized; 6 percent are distant.

That gap between 100.0 and 33.8 percent is the entire argument for screening. These are registry averages describing a population rather than any individual, and they cover all subtypes together.

What this does and doesn't change

It is a recommendation for average risk. It is not a plan for someone with a strong family history, a known genetic variant, or prior chest radiation.

The interval is still contested. The task force says every two years; ACS offers annual from 40. That is a live disagreement, not settled fact.

It says nothing about women over 74, and nothing about what to add for dense breasts. Both were left open for want of evidence.

And a guideline is a judgment about a population. Whether it fits one person depends on their risk, their history, and what they want from a test.

Sources

• US Preventive Services Task Force, Breast Cancer: Screening, final recommendation 30 April 2024 — https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/breast-cancer-screening
• NCI, Mammograms fact sheet — https://www.cancer.gov/types/breast/mammograms-fact-sheet
• American Cancer Society, ACS Supports Updated USPSTF Breast Cancer Screening Guidelines, 30 April 2024 — https://pressroom.cancer.org/releases?item=1320
• SEER Cancer Stat Facts, Female Breast Cancer — https://seer.cancer.gov/statfacts/html/breast.html

How this article was prepared

An AI-assisted editorial system helped prepare this page. No named medical reviewer has reviewed it unless one is listed.

The National Cancer Information Foundation publishes Cancer Explained. This page is for learning. It is not medical advice and does not suggest a test or treatment.

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