At what age should women start getting screening mammograms?

Screening Mammography Age Recommendations

Women at average risk should begin annual screening mammography at age 40 to maximize mortality reduction and life-years saved. 1, 2, 3, 4

Starting Age for Average-Risk Women

The most recent and highest-quality evidence from the American College of Radiology (ACR) 2024 guidelines establishes that:

• Annual screening should begin at age 40 for all average-risk women, as this provides a 40% mortality reduction compared to only 23% when screening starts at age 50 with biennial intervals 1
• Starting at age 40 rather than 45 or 50 saves significantly more lives—annual screening from age 40-84 prevents 12 deaths per 1,000 women screened versus only 7 deaths per 1,000 with biennial screening from age 50-74 1
• Women aged 40-49 experience a 15-50% reduction in breast cancer mortality with screening, and are less likely to require mastectomy or chemotherapy when cancers are detected early 1

The evidence strongly supports age 40 as the optimal starting point, though some organizations offer qualified recommendations allowing women to begin between ages 40-44 based on individual preference 1, 2, 3

Screening Frequency by Age Group

Ages 40-54

• Annual mammography is recommended to maximize mortality benefit 1, 2, 3
• Annual screening in women 40-49 saves 42% more lives than biennial screening due to faster-growing tumors in younger women 1

Ages 55 and Older

• Women may continue annual screening or transition to biennial screening based on individual preference 1, 2, 3
• Annual screening provides greater mortality reduction (40%) compared to biennial screening (32%) across all ages 40-84 1

Upper Age Limit Considerations

There is no established upper age limit for screening mammography. 1, 2, 3

• Women should continue screening as long as overall health is good and life expectancy exceeds 5-10 years 1, 2, 3
• Screening decisions should be based on life expectancy and comorbidities rather than age alone 1, 2
• Observational studies demonstrate continued benefit for women age 75 and older 1

Special Population Considerations

Minority Women

• Delaying screening disproportionately impacts minority women, who present at younger ages with more aggressive tumor subtypes and have higher mortality rates 1, 4

Dense Breasts

• Women with dense breasts have decreased mammographic sensitivity and 1.2-2.1 times higher breast cancer risk depending on density category 1
• Digital breast tomosynthesis (DBT) increases cancer detection rates and decreases false-positive recalls compared to standard 2-D mammography, with particular benefit in women under 50 and those with dense breasts 1, 3

Balancing Benefits and Harms

Benefits

• 40% mortality reduction with annual screening starting at age 40 1, 4
• Earlier stage at diagnosis, smaller tumors, and better treatment options 1, 4
• Greater life-years gained when screening begins at age 40 due to longer life expectancy 1, 3

Harms

• Approximately 10% of screening mammograms result in recall, with less than 2% leading to biopsy recommendation 2, 3
• False-positives and screening-related anxiety occur but research shows women value early detection over these concerns 1
• Higher recall rates in younger women, though this is offset by greater life-years saved 1, 4

Common Pitfalls to Avoid

• Do not delay screening to age 45 or 50 for average-risk women—this results in unnecessary loss of life, particularly among minority populations 1, 4
• Do not stop screening prematurely at age 74—continue as long as life expectancy exceeds 5-10 years 1, 2
• Do not recommend clinical breast examination as a screening tool—the ACS does not support this practice 1, 3