Breast Cancer Risk Assessment Tool

The National Cancer Institute (NCI) breast cancer risk assessment tool (also known as the “Gail model”) uses personal risk factors to help estimate a woman’s risk of developing breast cancer. Each woman’s risk of developing breast cancer is different. Personal and family health histories as well as lifestyle factors influence breast cancer risk. Knowing your breast cancer risk can help you make decisions about your health. 

The Tool 

The following information is used to estimate your breast cancer risk.

• Your age: Your risk of developing breast cancer increases as you get older. 
• Your age when you had your first period: Starting your period before age 12 slightly increases your breast cancer risk. 
• Your age when you had your first child: Having your first child at age 30 or older or never having children increases your risk of breast cancer. 
• The number of your first-degree relatives – mother, sisters, or daughters – who have had breast cancer: Having first-degree relatives who have had breast cancer increases your risk. 
• Your history of breast biopsies: Women who have had biopsies may have an increased risk of breast cancer. If the biopsy found “atypical” cells, your risk of developing breast cancer is greatly increased. The biopsy itself does not increase your risk of breast cancer. 
• Your race or ethnicity: Ethnicity has an effect on breast cancer risk. White women have the highest breast cancer risk, followed by African Americans, Asians, Hispanics, and American Indians. 

The Results 

This tool estimates your risk of developing breast cancer over the next five years and in your lifetime (up to age 90 years). It compares your risk to that of the average woman who is your same age and race. Your risk is given as a percentage.

The five-year risk estimates your risk of developing breast cancer over the next five years. If the results show your five-year risk is 1.7% or higher, this means you have an increased risk of developing breast cancer.  Of note, women in their 60s and older may have a five-year risk greater than 1.7% based on age alone, as increasing age is a risk factor for breast cancer. 

The lifetime risk estimates your risk of developing breast cancer over your lifetime. If the results show your lifetime risk is 20% or higher, this means you have an increased risk of developing breast cancer compared to an average woman.

In addition, women with a history any of the following are at increased risk: 

• Atypical ductal or lobular hyperplasia.
• Lobular carcinoma in situ.
• A mutation in a hereditary breast cancer gene (such as BRCA1 or BRCA2). 
• Chest radiation therapy between the ages of 10 and 30 years.

If you have an increased risk of breast cancer, talk with your health care provider. Your healthcare provider may be able to suggest ways to manage your risk, such as lifestyle changes, more frequent and specialized breast exams and imaging, as well as medicines and surgeries. 

Accuracy

This tool provides a good estimate of breast cancer risk for most women. It does have some weaknesses. The following list explains these weaknesses: 

• The tool may overestimate the risk of developing breast cancer for certain ethnicities. 
• The tool does not ask about all family members with breast cancer, such as grandmothers, aunts or men in the family. Nor does it ask about the age of diagnosis of family members. If you have additional family members with breast cancer or family members diagnosed at a young age, talk with your healthcare provider about other models that might better assess your risk. 
• The tool does include other factors that may influence breast cancer risk, such as breast density, age at menopause, or use of hormone therapy.