When to Start Mammogram Screening
Women with average risk of breast cancer should begin regular mammography screening at age 45, with annual screening from ages 45-54 and biennial screening at age 55 and older, continuing as long as they are in good health with a life expectancy of at least 10 years. 1, 2
Screening Recommendations by Age Group
Ages 40-44
- Women should have the opportunity to begin annual screening between ages 40-44 years 1, 2
- This is a qualified recommendation, indicating that while there is clear evidence of benefit, there is less certainty about the balance of benefits and harms 1
- The American College of Radiology recommends annual screening beginning at age 40 1
- Women who place higher value on potential benefits than potential harms may choose to begin screening in this age range 1
Ages 45-54
- Annual screening is strongly recommended 1, 2
- This age group shows more favorable benefit-to-harm ratio than younger women 1
Ages 55 and older
- Women should transition to biennial screening or have the opportunity to continue annual screening 1, 2
- Screening should continue as long as overall health is good and life expectancy is 10+ years 1, 2
Risk-Based Considerations
Average-Risk Women
- Average risk is defined as women without a personal history of breast cancer, suspected or confirmed genetic mutation (e.g., BRCA), or history of chest radiation at a young age 1
- The screening algorithm above applies to average-risk women
Higher-Risk Women
- All women should undergo risk assessment by age 25-30 to identify those at higher-than-average risk 1, 3
- Women with genetics-based increased risk, calculated lifetime risk ≥20%, or chest radiation exposure at young ages require more intensive screening 1, 3
- For women with a family history of breast cancer, screening should begin 10 years prior to the youngest age at presentation in the family, but generally not before age 30 1
- Supplemental screening with MRI is recommended for high-risk women 1, 3
Benefits and Harms of Screening
Benefits
- Reduction in breast cancer mortality (approximately 40% with regular screening) 4
- Earlier detection allows for less invasive treatment options 1
- Annual screening results in more screening-detected tumors, smaller tumor sizes, and fewer interval cancers than longer screening intervals 4
Harms
- False-positive results leading to additional testing and anxiety
- Unnecessary biopsies
- Overdiagnosis of cancers that may not have become clinically significant
- For every 1000 women screened biennially starting at age 50, approximately 953 false-positive results and 146 unnecessary biopsies can occur 2
Special Considerations
Dense Breasts
- Women with dense breasts may benefit from supplemental screening 1, 3
- Digital breast tomosynthesis (DBT) may improve cancer detection rates and decrease false-positive recalls, particularly for women with dense breasts 1
Screening Modalities
- Mammography remains the gold standard screening modality for average-risk women 5
- Clinical breast examination is not recommended for breast cancer screening among average-risk women at any age 1
Common Pitfalls to Avoid
Delaying screening until age 50: This can result in missed opportunities for early detection, particularly for the 1 in 6 breast cancer cases that occur in women between ages 40-49 6
Stopping screening based on age alone: Screening should continue as long as a woman is in good health with a life expectancy of at least 10 years, rather than stopping at an arbitrary age 1, 2
Failing to assess individual risk: All women should undergo risk assessment by age 25-30 to identify those who may benefit from earlier or more intensive screening 1, 3
Overlooking the importance of screening frequency: Annual screening in the 45-54 age group provides greater mortality reduction than biennial screening 1, 4
By following these evidence-based recommendations, women can maximize the benefits of breast cancer screening while minimizing potential harms.