What are good resources for calculating breast cancer risk?

Best Resources for Breast Cancer Risk Calculation

The NCI Breast Cancer Risk Assessment Tool (Gail model) is the most commonly used and accessible resource for patients to calculate their breast cancer risk, though specialized models like Tyrer-Cuzick, Claus, BRCAPRO, and BOADICEA are more appropriate for women with significant family history. 1

Overview of Available Risk Assessment Tools

Primary Tools for General Population:

• NCI Breast Cancer Risk Assessment Tool (Gail model)
  • Available at: http://www.cancer.gov/bcrisktool
  • Most commonly used in the United States 1
  • Provides 5-year and lifetime risk estimates
  • Based on age, ethnicity, history of breast biopsy, breast cancer history, age at menarche, parity, and age at first live birth 1
  • Validated for women age 35 years or older 1

Specialized Tools for Women with Strong Family History:

• Tyrer-Cuzick (IBIS) Model

  • More comprehensive for family history analysis
  • Shows better calibration and discrimination across risk levels 2
  • Performs better than Gail model in women with family history 3, 4

• Claus Model

  • Specifically designed for detailed family history analysis 1

• BRCAPRO Model

  • Estimates both breast cancer risk and likelihood of BRCA mutation 1

• BOADICEA Model

  • Analyzes complex family histories
  • Estimates carrier probability for BRCA genes 1

When to Use Each Model

Use Gail Model When:

• Patient is ≥35 years old
• Patient has average risk factors
• No significant family history of breast/ovarian cancer
• Need to determine if 5-year risk is ≥1.66% (threshold for chemoprevention consideration) 1, 5

Use Specialized Models (Tyrer-Cuzick, Claus, BRCAPRO, BOADICEA) When:

• Strong family history (two or more first/second-degree relatives with breast cancer) 1
• Family history of early-onset breast cancer (before age 50) 1
• Family history of ovarian cancer 1
• Need to assess BRCA mutation probability 1
• Need to determine if lifetime risk is ≥20-25% (threshold for MRI screening) 1

Important Limitations to Consider

1. Model Agreement Issues:

   • Weak agreement between different models, especially for women in their 40s 6
   • Different models may lead to different clinical recommendations 6

2. Underestimation Concerns:

   • Gail model underestimates risk in women with family history 4
   • Gail model does not adequately account for paternal family history 1

3. Population-Specific Considerations:

   • Women's Contraceptive and Reproductive Experiences (CARE) model provides more sensitive estimates for African American women 1
   • Gail model may not be appropriate for all ethnic groups 1

Clinical Application

1. For Primary Care Providers:

   • Consider using FHS-7 questionnaire as initial screening tool in primary care 4
   • Use positive family history responses to determine which risk model is most appropriate

2. For High-Risk Assessment:

   • Women with calculated lifetime risk ≥20% should be referred to specialized high-risk clinics 1
   • Consider genetic counseling for women with multiple affected relatives or early-onset breast cancer 1

3. For Chemoprevention Decisions:

   • 5-year risk of 1.66% using Gail model is often used as threshold 1, 5
   • Risk/benefit assessment should be individualized based on model results 5

Remember that risk models should be used as part of a comprehensive approach to breast cancer risk assessment and not as the sole determinant for clinical decisions. Periodic reassessment is recommended as a woman's risk changes throughout her lifetime.