The American College of Obstetricians and Gynecologists (ACOG) has updated its breast cancer screening guidance to recommend that all individuals at average risk begin routine mammography at age 40, a shift driven by rising cancer rates in younger women and efforts to address racial health inequities. This new recommendation aligns ACOG with other major health organizations and represents a meaningful change from previous guidance that suggested screening could wait until age 50 for those who hadn't started in their 40s.

Why Are Doctors Lowering the Screening Age?

The decision to recommend earlier screening stems from several converging trends. New cases of invasive breast cancer among women ages 40 to 49 increased by an average of 2% per year from 2015 to 2019, demonstrating a concerning shift toward younger diagnoses. This rising incidence, combined with evidence showing that earlier detection leads to better outcomes, prompted ACOG to strengthen its recommendation.

Beyond the numbers, the updated guidance addresses a critical health equity issue. Black women experience the highest rate of breast cancer mortality among all women, even when accounting for age and cancer stage at diagnosis. They also have a higher incidence of triple-negative breast cancer, an aggressive form that typically appears at a younger age and is often diagnosed at a more advanced stage.

"There has been a concerning trend of increasing breast cancer diagnoses among women in their 40s, and new data shows that earlier screening could make a significant difference in decreasing breast cancer deaths. While screening can sometimes cause anxiety for people and even unnecessary follow-up, the benefits of diagnosing breast cancer earlier outweigh those risks enough to warrant starting to get mammograms at age 40," said Eve Zaritsky, MD, FACOG, named author of the clinical practice update.

Eve Zaritsky, MD, FACOG, American College of Obstetricians and Gynecologists

How Does Earlier Screening Address Health Disparities?

Racial and ethnic disparities in breast cancer care extend beyond diagnosis rates. Hispanic, Asian, and American Indian and Alaskan Native women experience delays in screening follow-up, diagnosis, and treatment, contributing to worse overall outcomes. By recommending universal screening at age 40, ACOG hopes to create more equitable access to early detection across all populations.

"Our updated recommendation addresses important inequities in breast cancer diagnosis, treatment, and death, and we hope that the earlier initiation of mammography screening across the board will have a great net benefit in outcomes for Black women especially, who have been shown to have the poorest outcomes when it comes to breast cancer, in part because of long-standing inequities in social determinants of health," stated Cherie C. Hill, MD, FACOG, named author of the clinical practice update.

Cherie C. Hill, MD, FACOG, American College of Obstetricians and Gynecologists

What Do the Updated Screening Recommendations Include?

ACOG's interim update to Practice Bulletin 179 provides clear guidance for patients and clinicians. The key recommendations are:

• Starting Age: All individuals at average risk of breast cancer should begin screening mammography at age 40, rather than waiting until age 50.
• Screening Frequency: Screening mammography should occur every one or two years based on an informed, shared decision-making process between patients and their clinicians, allowing for personalized care plans.
• Alignment with Other Guidelines: This recommendation is now consistent with guidance from the U.S. Preventative Services Task Force (USPSTF), the National Comprehensive Cancer Network, the American College of Radiology, and the Society of Breast Imaging, reducing confusion among healthcare providers and patients.

The emphasis on shared decision-making is important. Screening can sometimes lead to anxiety or unnecessary follow-up procedures, so conversations between patients and their doctors about individual risk factors and preferences remain central to the approach.

"With the recent evidence demonstrating overall benefit of starting mammogram screening for breast cancer at age 40, we hope that there will be more consensus among the different guidelines to decrease confusion for clinicians and patients and ultimately ensure that people are able to start screening earlier," noted Melissa Joy Chen, MD, MPH, FACOG, named author of the clinical practice update.

Melissa Joy Chen, MD, MPH, FACOG, American College of Obstetricians and Gynecologists

What Happens Next?

The clinical practice update is available online now and will be published in the January 2025 issue of Obstetrics and Gynecology, the official journal of ACOG. This publication will make the guidance widely accessible to obstetricians, gynecologists, and other healthcare providers who counsel patients on cancer prevention.

While the updated screening recommendation represents progress, ACOG acknowledges that structural inequities in healthcare remain a significant barrier to equitable breast cancer outcomes. Addressing these disparities will require ongoing efforts beyond screening alone, including improvements in access to timely diagnosis, treatment, and supportive care across all communities.