At what age should breast cancer screening begin?

Breast Cancer Screening Age Guidelines

Women with average risk of breast cancer should undergo regular screening mammography starting at age 45 years, with the opportunity to begin annual screening between ages 40-44 years based on individual preference. 1

Screening Recommendations by Risk Category

Average-Risk Women:

• Starting age: 45 years (strong recommendation) 1
• Ages 45-54: Annual screening (qualified recommendation) 1
• Ages 55+: Biennial screening or option to continue annual screening (qualified recommendation) 1
• Ages 40-44: Option to begin annual screening (qualified recommendation) 1
• Continuation: As long as overall health is good and life expectancy is 10+ years 1

Higher-Risk Women:

• Starting age: Earlier than average-risk women, based on specific risk factors 1, 2
• Women with genetics-based increased risk (BRCA mutations), calculated lifetime risk ≥20%, or history of chest radiation at young age should begin MRI surveillance at ages 25-30 1, 2
• Black women and those of Ashkenazi Jewish descent should be evaluated for breast cancer risk by age 30 1

Screening Modalities

Primary Screening:

• Mammography: Gold standard for average-risk women 1
• Clinical breast examination: Not recommended for breast cancer screening among average-risk women (qualified recommendation) 1

Supplemental Screening for Higher-Risk Women:

• MRI: Recommended for women with genetics-based increased risk, calculated lifetime risk ≥20%, history of chest/mantle radiation therapy at young age 1, 2
• MRI: Also recommended for women with personal histories of breast cancer and dense tissue, or those diagnosed by age 50 1
• Ultrasound: Can be considered for those who qualify for but cannot undergo MRI 1

Benefits vs. Harms of Screening

Benefits:

• Early detection decreases breast cancer mortality 1, 3
• Mortality reduction of up to 40% is possible with regular screening 3
• Earlier stage diagnosis, better surgical options, and more effective chemotherapy 3

Potential Harms:

• False positives requiring additional imaging or biopsies 1
• Anxiety related to recalls and biopsies 1, 3
• Possibility of overdiagnosis 1
• Radiation exposure from repeated mammograms 4

Important Considerations

• Breast cancer incidence increases with age, with significant increases beginning in the 40s (122.5 per 100,000 for ages 40-44 and 188.6 per 100,000 for ages 45-49) 1
• Mammography sensitivity is lower in younger women (approximately 75% for women under 50 vs. 85% for women over 50) 4
• The American College of Radiology recommends annual mammography screening beginning at age 40 for women of average risk 3
• The American Cancer Society updated its guidelines in 2015, changing from recommending screening at age 40 to age 45 1

Common Pitfalls to Avoid

• Failing to conduct risk assessment by age 30 for high-risk women, especially Black women and those of Ashkenazi Jewish descent 1, 5
• Continuing screening in women with life expectancy less than 10 years 1, 5
• Relying solely on mammography for high-risk women or those with dense breasts 5, 2
• Delaying screening until age 50, which may result in unnecessary loss of life to breast cancer, particularly affecting minority women 3

Decision Algorithm for Breast Cancer Screening

1. Assess risk factors by age 30:

   • Family history of breast/ovarian cancer
   • Known genetic mutations (BRCA1/2)
   • History of chest radiation at young age
   • Race/ethnicity (Black women and Ashkenazi Jewish women at higher risk)

2. For average-risk women:

   • Begin regular screening at age 45
   • Consider starting at age 40-44 based on individual preference
   • Screen annually ages 45-54
   • At age 55+, transition to biennial screening or continue annually
   • Continue as long as overall health is good and life expectancy exceeds 10 years

3. For higher-risk women:

   • Begin screening earlier (ages 25-30) with appropriate modalities
   • Use supplemental screening with MRI when indicated
   • Consider more frequent screening intervals

The evidence clearly supports beginning breast cancer screening at age 45 for average-risk women, with the option to begin at age 40, and continuing as long as a woman is in good health with a life expectancy of at least 10 years.