How often should women undergo mammography (mammogram) for breast cancer screening?

Breast Cancer Screening Mammography Recommendations

Women should undergo annual mammography screening starting at age 45, transition to biennial screening at age 55, and continue as long as they have good health with a life expectancy of at least 10 years. 1, 2

Age-Specific Screening Recommendations

Ages 40-44

• Women should have the opportunity to begin annual screening between ages 40-44 (qualified recommendation) 1
• This is particularly important for:
  • Women with extremely dense breasts, as biennial screening in this age group with extremely dense breasts is associated with increased risk of advanced-stage cancer (OR 1.89) and larger tumors (OR 2.39) 3
  • Black women and women of Ashkenazi Jewish heritage who should undergo risk assessment by age 25 2

Ages 45-54

• Women should undergo regular screening mammography beginning at age 45 (strong recommendation) 1
• Annual screening is recommended for this age group (qualified recommendation) 1
• Annual screening in this age group saves 42% more lives than biennial screening due to faster-growing tumors in younger women 1

Ages 55 and older

• Women should transition to biennial screening or have the opportunity to continue annual screening (qualified recommendation) 1
• Screening should continue as long as overall health is good and life expectancy is 10 years or more 1, 2
• No specific upper age limit exists for screening mammography 1

Benefits of Screening

• Annual screening mammography for women 40-84 years decreases mortality by 40% (12 lives per 1,000 women screened) 1
• Biennial screening for women 50-74 years decreases mortality by 23% (7 lives per 1,000 women screened) 1
• Women screened between 40-49 years are less likely to require mastectomy or chemotherapy than women diagnosed with palpable tumors 1

Considerations for Special Populations

• Non-Hispanic black women, Hispanic black, and Hispanic white women have higher breast cancer mortality and often present at younger ages with more aggressive tumor subtypes 1
• Hispanic women aged 50-74 years who screen biennially versus annually have an increased risk of late-stage disease (OR 1.6) and large tumors (OR 1.6) 4
• Asian women aged 40-49 years who undergo biennial screening have an elevated risk of positive lymph nodes (OR 3.1) 4
• Women with dense breasts should consider supplemental screening with MRI (preferred) or alternatives such as contrast-enhanced mammography or ultrasound 2

Potential Harms and Limitations

• False-positive risks decrease markedly with longer screening intervals 3, 4
• Cumulative probability of false-positive results is high among women undergoing annual mammography with extremely dense breasts who are either aged 40-49 years (65.5%) or using estrogen plus progestogen (65.8%) 3
• Lower cumulative risk of false-positive results occurs among women aged 50-74 years who undergo biennial or triennial mammography with scattered fibroglandular densities (30.7% and 21.9%, respectively) or fatty breasts (17.4% and 12.1%, respectively) 3

Clinical Breast Examination

• Clinical breast examination is not recommended for breast cancer screening among average-risk women at any age (qualified recommendation) 1
• Women should be informed about the benefits, limitations, and potential harms associated with regular screening 1, 2

Common Pitfalls to Avoid

1. Failing to recognize that screening benefits vary by age and breast density
2. Continuing screening in women with life expectancy less than 10 years 2
3. Relying solely on mammography for high-risk women or those with dense breasts 2
4. Not considering that decreasing access to screening mammography, especially in women 40-49 years, may disproportionately impact minority women 1
5. Overlooking the need for risk assessment by age 25 for high-risk women 2

By following these evidence-based recommendations, clinicians can help maximize the benefits of breast cancer screening while minimizing potential harms for their patients.