At what age should women with average and high risk of breast cancer start annual breast cancer screening?

Breast Cancer Screening: When to Start

For average-risk women, begin annual mammography screening at age 45 years, with the option to start at age 40 based on informed patient preference. 1, 2

Average-Risk Women: Age-Based Algorithm

Ages 40-44 Years

• Offer the opportunity to begin annual screening mammography after discussing benefits and harms 1, 2
• This is a qualified recommendation reflecting clear benefit but less certainty about the balance of harms (false positives, anxiety, overdiagnosis) 1
• Younger women gain more life-years when cancer is detected early due to longer life expectancy, though more screening is required per life saved 3

Ages 45-54 Years

• Begin annual screening mammography - this is a strong recommendation 1, 2
• The American Cancer Society's strong recommendation at age 45 reflects consensus that benefits clearly outweigh harms at this age 1
• Annual screening provides maximum mortality benefit in this age group 3

Ages 55 Years and Older

• Transition to biennial (every 2 years) screening, or continue annual screening based on patient preference 1, 2
• Continue screening as long as overall health is good and life expectancy exceeds 10 years 1, 2

Important Caveat for Average-Risk Screening

• Clinical breast examination is NOT recommended for screening at any age in average-risk women 1, 2
• This represents a significant departure from older guidelines that recommended clinical breast examination 1

High-Risk Women: Earlier and More Intensive Screening

When to Start at Age 25-30 Years

Begin annual MRI plus annual mammography at age 25-30 for women with: 4, 5

• BRCA1/2 mutations (lifetime risk 45-85%) - start at age 25-30 4, 5
• Calculated lifetime risk ≥20% using Tyrer-Cuzick, BRCAPRO, or Claus models - start at age 30 4, 5
• History of chest radiation ≥10 Gy before age 30 (e.g., Hodgkin lymphoma treatment) - start at age 25 or 8 years after radiation, whichever is later 4, 5
• Other high-risk genetic mutations including TP53, PTEN, CDH1, STK11, PALB2, ATM 4

When to Start at Age 30 Years

Begin annual mammography plus annual MRI at age 30 for: 4, 5

• Women with 20% or greater lifetime risk based on family history models 4, 5
• Women with strong family history even without identified genetic mutation 4

Special Consideration: Family History Without Genetic Testing

Start screening 10 years younger than the youngest affected first-degree relative, but generally not before age 30 4

Personal History of Breast Cancer

Begin annual mammography plus MRI for: 4, 5

• Women diagnosed with breast cancer before age 50 (≥20% lifetime risk for new breast cancer) 4, 5
• Women with personal history of breast cancer and dense breasts 4, 5

Critical Pitfall to Avoid

• Do NOT apply standard population screening guidelines (starting at age 40-50) to women with significant family history or genetic risk factors 4
• All women should undergo risk assessment by age 25-30, with particular emphasis on Black women and those of Ashkenazi Jewish descent who have higher rates of actionable genetic mutations 4, 5

Screening Modality for High-Risk Women

Primary Recommendation

• Annual breast MRI with IV contrast PLUS annual mammography (can be performed concomitantly or alternating every 6 months) 4, 5
• MRI combined with mammography achieves 91-98% sensitivity versus 23% for mammography alone in high-risk women 4
• MRI detects an additional 8-29 cancers per 1,000 examinations in elevated-risk women 4

When MRI Cannot Be Performed

• Contrast-enhanced mammography is the preferred alternative (detects 6.6-13 additional cancers per 1,000) 4
• Whole breast ultrasound may be considered only when MRI is contraindicated or unavailable, though it has substantially higher false-positive rates 4
• Molecular breast imaging is NOT recommended for any high-risk screening 4

Key Differences Between Guidelines

There is notable divergence between major organizations on the starting age for average-risk women:

• American College of Radiology: Strongly recommends starting at age 40 for all average-risk women 3
• American Cancer Society: Strong recommendation to start at age 45, with option at age 40 1, 2
• The difference reflects varying assessments of the benefit-to-harm ratio in the 40-44 age group 6, 7

The most recent high-quality guideline evidence (2015 American Cancer Society in JAMA) supports age 45 as the strong recommendation, with age 40-44 as a qualified recommendation requiring shared decision-making 1