ACP Recommends Biennial Mammograms for Women Aged 50 to 74

The American College of Physicians (ACP) has reaffirmed its recommendation that women aged 50 to 74 undergo biennial mammography screening for breast cancer, emphasizing that this interval provides an optimal balance between early detection and minimizing potential harms from overdiagnosis and false positives.

This guidance, reiterated in a clinical guideline published in the Annals of Internal Medicine, aligns with the ACP’s long-standing position that screening every two years is sufficient for average-risk women in this age group, as annual screening does not significantly reduce breast cancer mortality but increases the likelihood of unnecessary biopsies, anxiety, and treatment of cancers that would not have caused harm during a woman’s lifetime.

The ACP’s recommendation is based on a comprehensive review of randomized controlled trials and observational studies evaluating the benefits and risks of different mammography screening intervals. The organization concluded that while mammography reduces breast cancer mortality, the absolute benefit is modest, and biennial screening captures most of this benefit while reducing the cumulative risk of false-positive results by nearly half compared to annual screening.

False-positive mammograms, which occur when an abnormality is detected that turns out not to be cancer, can lead to additional imaging, biopsies, and significant psychological distress. The ACP notes that over a 10-year period, approximately half of women who undergo annual screening will experience at least one false-positive result, compared to about one-quarter of those screened biennially.

Overdiagnosis — the detection of cancers that would never progress to cause symptoms or death — remains a critical concern in breast cancer screening. The ACP highlights that biennial screening reduces the likelihood of identifying such indolent cancers, thereby decreasing the chance that women will undergo surgery, radiation, or hormone therapy for lesions that pose no threat to their health.

The guideline applies specifically to women at average risk of breast cancer. The ACP advises that women with a personal history of breast cancer, a known genetic mutation such as BRCA1 or BRCA2, or a history of high-dose radiation therapy to the chest before age 30 should consult with their healthcare provider about earlier or more frequent screening, as these factors significantly increase risk and may warrant a different approach.

Dr. Amir Qaseem, Vice President of Clinical Policy at the ACP and an author of the guideline, stated that the recommendation reflects a commitment to evidence-based care that avoids both underuse and overuse of medical interventions. “Our goal is to ensure that women receive the proven benefits of mammography while minimizing exposure to unnecessary procedures and their associated harms,” he said.

The ACP’s stance is consistent with recommendations from other major health organizations, including the U.S. Preventive Services Task Force (USPSTF), which also advises biennial screening for women aged 50 to 74. In contrast, organizations such as the American Cancer Society and the American College of Radiology recommend annual screening starting at age 45 or 40, respectively, citing a desire to maximize early detection despite the trade-offs in false positives and overdiagnosis.

Despite these differences, all major guidelines emphasize the importance of informed decision-making. The ACP encourages clinicians to discuss the potential benefits, limitations, and harms of mammography with their patients, taking into account individual values, preferences, and risk factors, so that women can make choices that align with their health goals.

As breast cancer remains the most common cancer among women worldwide and a leading cause of cancer-related death, screening continues to play a vital role in reducing mortality. However, the ACP’s biennial recommendation underscores a growing recognition in preventive medicine that more frequent testing is not always better — and that the timing and frequency of screening must be carefully calibrated to maximize benefit while minimizing harm.