Does Annual Breast Cancer Screening Starting at Age 40 Offer Benefit?

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Investigators have found that annual breast cancer screening beginning at age 40 and continuing to at least 79 may result in the greatest reduction in mortality with minimal risks, according to a recent study published by Monticciolo et al in Radiology.


Breast cancer is the second most common cause of cancer mortality among women in the United States. Despite previous research demonstrating that consistent participation in screening mammography can reduce breast cancer mortality by 40%, only 50% or less of the eligible patients may be participating in annual screening.

"There is an ongoing debate over the recommendations for breast cancer screening, specifically about when to start and the frequency of screening," explained lead study author Debra L. Monticciolo, MD, Professor of Radiology at the Dartmouth Geisel School of Medicine. "The risks of screening are nonlethal and manageable for most women. [However], advanced breast cancer is often lethal. Breast cancer is easier to treat if it's found earlier; we're able to spare women extra surgeries and chemotherapy. It's just a better idea to shift to early detection, and that's what screening does,” she added.

In 2009, the U.S. Preventive Services Task Force (USPSTF) recommended that women screen for breast cancer biennially beginning at the age of 50. As a result, researchers noted a nationwide decline in screening participation. In 2023, the USPSTF drafted new recommendations suggesting that women participate in biennial screening between the ages of 40 and 74. The American College of Radiology, the Society of Breast Imaging, and the National Comprehensive Cancer Network recommend annual screening for women at average risk of developing breast cancer beginning at the age of 40 and continuing as long as they are in good health.

Study Methods and Results

In the recent study, the investigators performed a secondary analysis of Cancer Intervention and Surveillance Modeling Network (CISNET) 2023 median estimates of breast cancer screening outcomes at various frequencies and starting ages. They compared the benefits and risks of breast cancer screening—including mortality reduction, life-years gained, breast cancer–related deaths averted, benign or unnecessary biopsies, and recall rates—for four different scenarios: biennial screening in women aged 50 to 74 years, biennial screening in women aged 40 to 74 years, annual screening in women aged 40 to 74 years, and annual screening in women aged 40 to 79 years. CISNET did not offer modeling past the age of 79.

The investigators found that annual screening in women aged 40 to 79 years with either digital mammography or tomosynthesis reduced the mortality rate by 41.7%; whereas biennial screening in women aged 50 to 74 years and 40 to 74 years reduced the mortality rate by 25.4% and 30%, respectively. Further, annual screening in women aged 40 to 79 years showed the lowest per mammogram false-positive screens (6.5%) and benign biopsies (0.88%) compared with other screening scenarios.

Although the USPSTF used CISNET modeling to formulate its recommendations, it referred to recall rates and benign biopsies as harms, rather than risks. "To balance the harms and benefits of screening mammography, they're willing to give up some mortality benefit to avoid women being recalled for additional imaging and benign biopsies," Dr. Monticciolo said.

The investigators indicated the chance of a woman having a benign biopsy following annual breast cancer screening was less than 1%, and all recall rates for screening mammography were under 10%. When screening was performed annually with tomosynthesis, the recall rate decreased to 6.5%.


The investigators hope their findings will add to the body of literature that supports annual breast cancer screening beginning at age of 40 as the most effective strategy to diagnose this cancer type early. "The biggest takeaway … of our study is that annual screening beginning at [the age of] 40 and continuing to at least age 79 gives the highest mortality reduction, the most cancer deaths averted, and the most years of life gained. There's a huge benefit to screening annually until at least 79 and even more benefit if women are screened past 79," Dr. Monticciolo underscored.

"This paper is important because it shows once again that … the chances of experiencing harm are low on a per-exam basis. It comes down to valuing women's lives. I am hoping that primary care physicians see that risks of screening are manageable, and the benefits are tremendous. We need to do this for women,” she concluded.

Disclosure: For full disclosures of the study authors, visit

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