What are the guidelines for mammogram screenings?

Mammography Screening Guidelines

Primary Recommendation for Average-Risk Women

Women should begin annual screening mammography at age 40 and continue annually through age 54, then transition to biennial screening at age 55 (though annual screening remains an option), continuing as long as life expectancy exceeds 10 years. 1, 2, 3

Age-Specific Screening Algorithm

Ages 40-44

• Annual mammography is recommended starting at age 40 for all average-risk women, as this provides the greatest mortality reduction (18-26% reduction in breast cancer deaths), allows detection of earlier-stage disease, and offers better surgical options compared to starting at age 45 or 50. 1, 3, 4
• The American College of Radiology strongly recommends annual mammography beginning no later than age 40 for all average-risk women. 1, 2, 3

Ages 45-54

• Annual screening mammography is strongly recommended, as this age group shows the clearest benefit-to-harm ratio for annual screening. 1, 2, 3
• This represents the period of highest screening benefit relative to potential harms. 2

Ages 55-74

• Transition to biennial (every 2 years) screening at age 55, though women may continue annual screening based on individual preference. 1, 2, 3
• Biennial screening provides adequate mortality benefit (at least 22% reduction in randomized trials, up to 40% in observational studies) with fewer false-positive results in this age group. 1, 2, 3

Age 75 and Older

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

Clinical Breast Examination Recommendations

• For women ages 20-39: Clinical breast examination every 3 years during periodic health examinations. 2, 3
• For women ages 40 and older: Annual clinical breast examination, preferably scheduled close to and before the annual mammogram. 2, 3
• Clinical breast examination is not recommended as a standalone screening method for average-risk women. 1, 2

Breast Self-Examination

• Beginning in their 20s, women should be counseled about the benefits and limitations of breast self-examination (BSE). 2, 3
• Emphasize the importance of prompt reporting of any new breast symptoms to a health professional. 2
• Women may choose to perform BSE, perform it irregularly, or not perform it at all. 5

Benefits of Screening

• Mammography screening reduces breast cancer mortality by at least 22% in randomized trials, with observational studies showing up to 40% reduction in women who are actually screened. 1, 2, 3
• Starting at age 40 rather than 45 or 50 provides greater mortality reduction and allows detection of earlier-stage disease. 1, 3
• Annual screening results in more screening-detected tumors, smaller tumor sizes, and fewer interval cancers compared to longer screening intervals. 4

Harms and Limitations to Discuss

• Approximately 10% of screening mammograms result in recall for additional imaging, though less than 2% result in biopsy recommendation. 1, 2, 3
• False-positive results and unnecessary biopsies are more common in women aged 40-49 compared to older women. 1, 3
• For every 1,000 women screened biennially starting at age 40, there will be 1,529 false-positive results, 213 unnecessary biopsies, and 21 overdiagnosed cancer cases over their lifetime. 3
• Screening may detect cancers that would not have become clinically significant during a woman's lifetime (overdiagnosis). 2

Special Populations Requiring Earlier or Enhanced Screening

Family History

• Women with family history of breast cancer should begin screening 10 years prior to the youngest age at presentation in the family, but generally not before age 30. 1, 2, 3

Genetic Mutations

• Women with BRCA1 or BRCA2 mutations should begin screening earlier and receive supplemental screening with contrast-enhanced breast MRI. 3, 6
• Untested first-degree relatives of women with genetic mutations should be screened as if they carry the mutation. 3
• Women with genetics-based increased risk should undergo MRI surveillance starting at ages 25-30 and annual mammography starting between ages 25-40 depending on the type of risk. 6

Calculated High Risk

• Women with calculated lifetime risk of 20% or more should receive annual mammography plus annual breast MRI. 3, 6

Radiation Exposure

• Women with history of chest or mantle radiation therapy at a young age should receive supplemental screening with MRI. 3, 6

Personal History

• Women with personal history of breast cancer require annual surveillance mammography. 1, 3
• Women diagnosed with breast cancer before age 50 or with personal histories of breast cancer and dense breasts should undergo annual supplemental breast MRI. 6

High-Risk Lesions

• Women with lobular neoplasia or atypical hyperplasia diagnosed before age 40 should undergo annual screening from time of diagnosis, but generally not before age 30. 1

Risk Assessment Timing

• All women, especially Black women and those of Ashkenazi Jewish descent, should be evaluated for breast cancer risk no later than age 30, so that those at higher risk can be identified and can benefit from supplemental screening. 3, 6

Advanced Imaging Modalities

• Digital breast tomosynthesis (DBT) increases cancer detection rates by 1.6-3.2 per 1,000 examinations compared to standard digital mammography. 1, 2
• DBT advantages are especially pronounced in women under age 50, those with dense breasts, and for detecting spiculated masses and asymmetries. 3

Quality Assurance

• Ensure referral to accredited mammography facilities with proper quality assurance programs. 2, 3
• Quality guidelines recommend a delay of no more than 60 days between screening and diagnosis for abnormal results, with longer delays associated with poorer outcomes. 3

Shared Decision-Making

• Women should have an opportunity to become informed about the benefits, limitations, and potential harms associated with regular screening. 5, 2, 3
• Discussions should emphasize the importance of awareness of family history of breast and ovarian cancers in first-degree and second-degree relatives on both maternal and paternal sides. 2, 3

Important Guideline Discordances

While the evidence presented above reflects the most comprehensive and recent guidelines, be aware that different organizations have varying recommendations:

• The American Cancer Society recommends starting screening at age 45 as a strong recommendation, with optional screening at ages 40-44. 1, 2
• The U.S. Preventive Services Task Force recommends biennial screening starting at age 50 for women aged 50-74 years, with individualized decisions for ages 40-49. 2, 3
• The American College of Radiology strongly recommends annual mammography beginning no later than age 40 for all average-risk women. 1, 2, 3

The recommendation to begin at age 40 is based on maximizing mortality reduction, as delaying screening until age 45 or 50 results in unnecessary loss of life to breast cancer and adversely affects minority women in particular. 4