At what age should women start getting mammograms?

When to Start Mammogram Screening

For average-risk women, begin annual screening mammography no later than age 40, as this provides the greatest mortality reduction compared to starting at age 45 or 50. 1, 2

Average-Risk Women

Standard Screening Age

• The American College of Radiology strongly recommends annual mammography beginning no later than age 40 for all average-risk women. 1, 2
• Starting at age 40 rather than 45 or 50 provides greater breast cancer mortality reduction (at least 22% in randomized trials, up to 40% in observational studies of women actually screened). 1, 2
• Women aged 40-49 who undergo screening experience an 18-26% mortality reduction. 2

Screening Frequency by Age

• Ages 40-54: Annual screening is recommended for maximum mortality benefit. 1, 2, 3
• Ages 55 and older: Women may transition to biennial screening or continue annually based on preference, though annual screening provides greater mortality reduction (40% vs 32%). 2, 4, 3
• Annual screening is more effective than biennial screening at all ages, though it does increase the number of false-positive examinations. 1

Duration of Screening

• Continue screening as long as overall health is good and life expectancy exceeds 10 years. 2, 3
• There is no agreed-upon upper age limit for screening mammography. 1, 3
• Base screening decisions on life expectancy and competing comorbidities rather than age alone. 1, 3

High-Risk Women (Earlier Screening Required)

Family History of Breast Cancer

• Begin annual screening 10 years before the age at which the youngest affected first-degree relative was diagnosed, but generally not before age 30. 1, 4
• This applies to women with first-degree relatives (mother, sister, daughter) diagnosed with breast cancer. 4

Genetic Predisposition

• Women with BRCA mutations or other genetic predispositions should begin annual screening at age 30 (or 10 years before youngest affected relative's diagnosis, whichever is earlier). 4, 5
• These women also require annual breast MRI as supplemental screening starting at ages 25-30. 5

Personal History of Breast Cancer or High-Risk Lesions

• Women with lobular neoplasia or atypical hyperplasia diagnosed before age 40 should begin annual screening at time of diagnosis, but generally not before age 30. 1, 4, 3
• Women with personal history of breast cancer should undergo annual mammography for surveillance. 1

History of Chest Radiation

• Women exposed to chest radiation (particularly for Hodgkin's disease) at young ages should begin screening at ages 25-30. 5

Dense Breasts

• Women with extremely dense breasts have a 2.1-fold increased risk of breast cancer and should be considered for earlier or enhanced screening. 1
• For women with dense breasts who desire supplemental screening, breast MRI is recommended; if MRI is unavailable, contrast-enhanced mammography or ultrasound may be considered. 5

Important Clinical Considerations

Benefits of Screening

• Mammography is the only screening modality proven to decrease breast cancer mortality. 1
• Screen-detected tumors are typically smaller and more likely to be node-negative, reducing treatment morbidity. 1
• Digital breast tomosynthesis (DBT) increases cancer detection rates by 1.6-3.2 per 1,000 examinations compared to standard digital mammography and decreases recall rates by 2.2%. 1, 4

Potential Harms

• Approximately 10% of screening mammograms result in recall for additional imaging, though less than 2% result in biopsy recommendation. 2, 4, 3
• False-positive results can cause anxiety and lead to additional testing. 3
• Some detected cancers may not have become clinically significant during a woman's lifetime (overdiagnosis). 2

Common Pitfalls to Avoid

• Do not delay screening until age 50 in average-risk women—mortality reduction is significantly greater when starting at age 40. 1
• Do not forget to assess family history—restricting screening to only women with first-degree family history would miss approximately 66% of potentially screen-detectable cancers in women under 50. 4
• Do not use age 30 as a minimum threshold rigidly—the 10-year rule for family history should generally not push screening before age 30, but genetic mutation carriers may benefit from MRI screening starting at age 25. 4, 5

Risk Assessment

• All women should undergo breast cancer risk assessment by age 25, especially Black women and women of Ashkenazi Jewish heritage. 5
• Women aged 20-39 should have clinical breast examination every 3 years during periodic health examinations. 2
• Women aged 40 and older should have annual clinical breast examination, preferably scheduled before the annual mammogram. 2