The American College of Physicians has issued updated guidance on breast cancer screening for asymptomatic, average-risk adult female patients, recommending biennial mammography among those aged 50 to 74 years, while emphasizing shared decision-making among patients aged 40 to 49 years and those aged 75 years or older or with limited life expectancy.

The guidance also advised that clinicians consider digital breast tomosynthesis (DBT) among patients with dense breasts but avoid supplemental magnetic resonance imaging (MRI) or ultrasonography in average-risk individuals.

The guidance was presented at a breaking news scientific plenary session during the American College of Physicians (ACP) Internal Medicine Meeting 2026 in San Francisco.

The recommendations were based on systematic reviews of high-quality international guidelines from the Canadian Task Force on Preventive Health Care, the European Commission Initiative on Breast Cancer, and the US Preventive Services Task Force.

Notably, these recommendations apply only to average-risk patients—defined as those without a personal history of breast cancer, high-risk breast lesions, known genetic mutations (eg, BRCA1/2), or prior high-dose chest radiation at a young age.

Ages 40 to 49 Years: Shared Decision-Making

Among patients aged 40 to 49 years, the ACP recommended an individualized approach rather than routine screening.

Clinicians should discuss breast cancer risk, patient values and preferences, and uncertainty around benefits and harms. Patients without a clear preference shouldn't be routinely screened, while those who choose screening may benefit most from biennial mammography.

Evidence showed no reduction in all-cause mortality in this age group, along with only a small reduction in breast cancer mortality. Screening was associated with a higher rate of harms, including false-positive results, biopsies, overdiagnosis, overtreatment, and psychological distress.

Decision modeling suggested that starting screening at age 40 vs 50 years could yield modest additional benefit but substantially increase harms, with findings based largely on indirect evidence and assumptions of full adherence.

Ages 50 to 74 Years: Biennial Mammography

Among patients aged 50 to 74 years, the ACP recommended biennial mammography, concluding that the benefits outweigh the harms in most patients.

Screening in this group was associated with reduced breast cancer mortality—particularly among those aged 50 to 69 years—as well as fewer invasive and advanced cancers. Harms, including overdiagnosis, interval cancers, and false-positive–related distress, remained present.

Although annual screening may detect slightly more cancers and reduce interval cancers, the practice may lead to substantially more false positives and biopsies without a clear additional mortality benefit. The ACP therefore favored biennial screening to balance the benefits, harms, and patient burden.

DBT may be offered through shared decision-making, but it is more costly and may have limited availability.

Age 75 Years and Older: Consider Discontinuation

Among patients aged 75 years or older—or those with limited life expectancy—the ACP recommended discussing whether to discontinue screening.

The evidence showed no clear mortality benefit beyond 74 years of age, with increased risks of overdiagnosis and additional testing. Screening may be unlikely to provide benefit in patients with a life expectancy of less than 5 years.

Patients who choose to continue screening may undergo biennial mammography, with reassessment every 2 years.

Dense Breasts: DBT May Be Considered, MRI and Ultrasound Not Recommended

Approximately 40% to 50% of patients aged 40 years or older have dense breasts (BI-RADS category C or D), which increases the risk of cancer and reduces mammography sensitivity.

The ACP recommended considering supplemental DBT, particularly after a negative mammogram. Evidence showed increased cancer detection in initial screening rounds, although the benefits were less clear in subsequent rounds. No supplemental screening modality has demonstrated a reduction in mortality.

The ACP didn't recommend supplemental MRI or ultrasonography in average-risk patients with dense breasts. MRI can detect more cancers and reduce interval cancers, but it is associated with substantially higher false-positive rates, additional biopsies, and potential adverse effects. Ultrasound may also increase detection but can lead to more recalls and biopsies without a clear net benefit.

DBT may involve increased radiation exposure depending on the technique, and the availability and cost should be considered.

Harms, Costs, and Disparities

Evidence reviewed by the ACP indicated that more screening may not necessarily lead to better outcomes.

Harms include false-positive results—particularly among younger patients—overdiagnosis and overtreatment, psychological distress, and additional testing and procedures.

Annual US breast cancer screening costs are estimated at $9 billion to $11 billion, about one-fourth of all cancer screening costs per year.

Modeling suggested that screening may avert more deaths and yield more life-years gained among Black patients compared with the general population but doesn't eliminate disparities. Increased screening intensity can also increase the harms.

Clinical Considerations

The ACP highlighted several important points for clinicians:

• Assess individual risk before initiating screening

• Recommendations don't apply to symptomatic or high-risk patients

• Dense breast tissue can obscure cancers (“masking effect”)

• Patients must be informed of breast density under the US Food and Drug Administration regulations

• Breast self-examination isn't recommended

• Clinical breast examination shouldn't be the sole screening modality (except in low-resource settings)

• Participation in a high-quality screening program is essential.

Limitations and Research Needs

Evidence gaps remain, including limited data for patients aged 40 to 49 years and those aged 75 years or older, a lack of mortality data for supplemental screening modalities, and uncertainty regarding optimal screening intervals.

Ongoing studies, including the Tomosynthesis Mammographic Imaging Screening Trial, are expected to provide additional evidence.

Disclosures

Two members of the ACP Clinical Guidelines Committee were recused from authorship and voting as a result of moderate-level conflicts of interest. The ACP reported that all financial and intellectual disclosures were declared and managed in accordance with its policies. Financial support for the development of the guidance came exclusively from the ACP’s operating budget.

Source: Annals of Internal Medicine

Editor's note: Following publication of this article, the American College of Radiology and Society of Breast Imaging issued a statement calling the new guidelines a step backward. [Read our coverage here.]