How often should a woman get a mammogram (mammography)?

Mammography Screening Recommendations for Women

Women should begin regular screening mammography 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

Age-Based Screening Algorithm

Women Ages 40-44

• Opportunity to begin annual screening between ages 40-44 based on personal preference and risk assessment 1
• Benefits in this age group are smaller than in older women, with greater uncertainty about risk reduction 1
• Decision should consider individual breast cancer risk factors and patient values regarding potential benefits and harms 1

Women Ages 45-54

• Strong recommendation for annual screening mammography starting at age 45 1
• Higher incidence of breast cancer in this age group compared to women in their early 40s 1
• Annual screening provides optimal mortality benefit during these years 1

Women Ages 55 and Older

• Transition to biennial screening (every 2 years) or continue annual screening based on personal preference 1
• Biennial screening maintains most mortality benefits while reducing potential harms 1
• Continue screening as long as overall health is good and life expectancy is 10+ years 1

When to Stop Screening

• No specific age cutoff; decision based on health status and life expectancy 1
• Women with life expectancy <10 years may not benefit from continued screening 1
• Consider comorbidities and functional status rather than chronological age alone 1

Risk Considerations

Average-Risk Women

• Follow the age-based algorithm above 1
• Average risk defined as women without personal history of breast cancer, known genetic mutations (e.g., BRCA), or previous chest radiation at young age 1

Higher-Than-Average Risk Women

• Earlier and/or more intensive screening recommended 2
• Risk assessment should be performed for all women by age 25 2
• Women with genetic mutations, calculated lifetime risk ≥20%, or chest radiation exposure at young age should begin MRI surveillance at ages 25-30 and mammography between ages 25-40 2

Benefits and Harms of Screening

Benefits

• Reduced breast cancer mortality 1, 3
• Earlier detection allows for less aggressive treatment options 1
• Greatest mortality reduction and life-years gained with annual screening starting at age 40 4

Potential Harms

• False-positive results leading to additional testing and anxiety 1
• Overdiagnosis of cancers that would not have become clinically significant 1
• Exposure to radiation (though minimal risk) 1, 5
• Lower sensitivity and specificity in younger women due to denser breast tissue 5

Clinical Breast Examination

• Current ACS guidelines do not recommend clinical breast examination for breast cancer screening among average-risk women at any age 1
• This represents a change from earlier guidelines that recommended clinical breast exams every 3 years for women in their 20s and 30s, and annually for women 40 and older 1

Common Pitfalls to Avoid

• Failing to discuss both benefits and potential harms of mammography screening with patients
• Using age alone as the sole criterion to discontinue screening in older women
• Overlooking risk assessment to identify women who may benefit from earlier or more intensive screening
• Assuming all guidelines are in agreement (they differ on starting age and screening intervals)
• Not recognizing that mammography sensitivity is lower in younger women with denser breast tissue

Guideline Variations

It's important to note that guidelines differ between organizations:

• American Cancer Society (2015): Start at 45, annual ages 45-54, biennial 55+ 1
• American College of Radiology: Annual screening beginning at age 40 1
• U.S. Preventive Services Task Force: Biennial screening ages 50-74, individual decision ages 40-49 1
• Canadian Task Force: Biennial screening ages 50-74, not recommended ages 40-49 1

The most recent and comprehensive evidence from the American Cancer Society (2015) provides the strongest guidance for clinical decision-making, balancing mortality benefits with potential harms across different age groups.