ACOG Updates Recommendation on When to Begin Breast Cancer Screening Mammography

Today, the American College of Obstetricians and Gynecologists (ACOG) published an interim update to its clinical guidance, Practice Bulletin 179: Breast Cancer Risk Assessment and Screening in Average-Risk Women. The new update recommends that all individuals at average risk of breast cancer should begin screening mammography at 40 years of age. ACOG continues to recommend screening mammography every one or two years based on an informed, shared decision-making process between patients and their clinicians.

ACOG previously recommended that individuals at average risk of breast cancer be offered screening mammography at age 40 and that those who had not initiated screening in their 40s begin screening mammography by age 50. However, new data and several other factors, such as an increasing incidence of invasive breast cancer in younger women, a demonstrated greater net benefit of earlier screening, and an opportunity to improve health inequities, led to the updated recommendation.

New cases of invasive breast cancer among women ages 40-49 increased by an average of 2% per year from 2015 to 2019, demonstrating the importance of earlier screening in identifying cases of invasive breast cancer within this age group.

"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. I am hopeful that more people getting screened earlier will mean less invasive treatments and better overall outcomes for those with breast cancer," said Eve Zaritsky, MD, FACOG, named author of the clinical practice update.

Additionally, earlier initiation of breast cancer screening may help reduce racial inequities in breast cancer outcomes for patients. Data have demonstrated that Black women have the highest rate of breast cancer mortality among all women, even when adjusting for age of the patient and stage of the cancer at diagnosis. Black women also have a higher incidence of triple-negative breast cancer, which is an aggressive form of breast cancer that occurs at a younger age and presents in a more advanced stage at diagnosis.

"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," said Cherie C. Hill, MD, FACOG, named author of the clinical practice update. "While earlier screening can make some improvements, there is still much work to be done in improving inequities and disparities in breast cancer care, and we hope that during this Breast Cancer Awareness Month, we can bring more attention to these issues."

The clinical practice update acknowledges that there are still structural inequities that must be addressed to further improve breast cancer care. For example, Hispanic, Asian, and American Indian and Alaskan Native women experience inequities such as delays in screening follow-up, diagnosis, and treatment.
The updated recommendation to begin routine screening at age 40 is consistent with guidelines from the U.S. Preventative Services Task Force, the National Comprehensive Cancer Network, the American College of Radiology, and the Society of Breast Imaging.

"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," said Melissa Joy Chen, MD, MPH, FACOG, named author of the clinical practice update.

The Clinical Practice Update is available online now and will be published in the January 2025 issue of Obstetrics & Gynecology. For additional information, see ACOG's full guideline on breast cancer screening, Practice Bulletin 179: Breast Cancer Risk Assessment and Screening in Average-Risk Women.