Why I Will Recommend Mammograms at Age 40

Andrew M. Kaunitz, MD


May 19, 2023

This transcript has been edited for clarity.

Recommendations regarding when to start and how often to have screening mammograms vary among professional societies, with some groups recommending initiation of annual screening at age 40 and others at age 45.

The US Preventive Services Task Force is an independent, volunteer group of experts that makes evidence-based recommendations about preventive services. Until recently, the Task Force recommended biennial screening beginning at age 50.

In May of this year, the Task Force released its draft guidance regarding mammography in average-risk women. This draft recommends starting biennial screening at age 40.

The Task Force's literature review notes that breast cancer incidence among women in their 40s has increased 2% annually between 2015 and 2019, a rate of increase faster than in prior years. These observations underlie the Task Force's turnaround regarding age of initiating screening mammograms.

Rates of screening mammography are at least as high in Black as in other women. However, Black women are more likely to be diagnosed with triple-negative tumors, which are more aggressive. In addition, breast cancers diagnosed in Black women are more likely to have an advanced tumor stage. Although these differences partially explain why case-fatality rates for breast cancer are higher in Black women, inequities related to screening and follow-up, as well as treatment, also play an important role.

Accordingly, while initiating mammography at age 40 should benefit all women, it may particularly benefit Black women.

Harms associated with screening mammography include unnecessary callbacks for diagnostic imaging, unnecessary biopsies, and overdiagnosis. Overdiagnosis refers to identification of cancers destined to not become clinically important during a woman's lifetime.

With respect to screening interval, the Task Force draft guidance indicates that "available evidence suggests a more favorable trade-off of benefits vs harms with biennial vs annual screening."

I now plan to recommend that my patients initiate screening mammography at age 40. With respect to screening interval, I will continue to engage in shared decision-making regarding biennial vs annual mammograms.

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