When should I get a mammogram?

The U.S. Preventive Services Task Force recommends that women at average risk of breast cancer have a screening mammogram every 2 years, from age 40 through age 74.

That is the 2024 version of the advice. The older 2016 version left the 40s to personal choice. The current one says plainly to start at 40. The Task Force gave it a B grade, meaning it found at least moderate benefit.

Why every 2 years, and why the range ends

Screening is a trade. Mammograms find cancers earlier, when they are easier to treat. They also call back people who turn out to be fine, and they miss some cancers. Most people who get a callback do not have breast cancer. Screening every 2 years keeps most of the benefit while cutting the number of false alarms.

The range ends at 74 because that is where the evidence ends. For women 75 and older the Task Force issued an I statement, meaning there was not enough evidence to weigh benefits against harms. That is not the same as advice to stop. If you are over 74 and in good health, it is a real conversation to have with your doctor.

Reasons to start earlier

Some people are told to begin sooner, screen more often, or add breast MRI.

• Harmful BRCA1 or BRCA2 gene changes. More than 60% of women who inherit one of these will develop breast cancer during their lifetime. Professional groups recommend starting younger and adding MRI to mammography.
• Chest radiation for a childhood cancer. The National Cancer Institute says to begin at age 25, or 8 years after radiation ended, whichever comes later.
• A strong family history, a past breast cancer, or certain biopsy findings. These may also move the start date.

What dense breasts change

Dense breast tissue looks white on a mammogram, and so does cancer. That is why mammography is more likely to miss cancer in dense breasts.

You will be told where you stand. The FDA published a rule on March 10, 2023 requiring every mammogram report to state whether your breast tissue is dense or not dense, and gave facilities 18 months to comply. Whether to add ultrasound or MRI after a dense result is still unsettled; the Task Force issued another I statement there. Bring the density line on your report to your next visit and ask what your team advises.

2D or 3D

Many centers now use digital breast tomosynthesis, often called a 3D mammogram. Combined with a standard mammogram, it finds more tumors than a standard mammogram alone. Whether it saves more lives is not yet known. A large study called TMIST is comparing the two directly.

Other guidelines, and what to do

Groups differ, which is why friends report different advice. The American Cancer Society says women 40 to 44 have the option of a yearly mammogram, women 45 to 54 should have one every year, and women 55 and older may switch to every other year or keep going yearly, as long as they are in good health and expect to live at least 10 more years.

A few practical points. Use a facility certified under the Mammography Quality Standards Act; the certificate must be displayed. Expect a plain-language summary of your results within 30 days. Bring or forward your old images, since comparison with last time is how small changes get caught. And check coverage before you worry about cost: most health plans must cover a screening mammogram every 1 to 2 years for women 40 and older with no copay.