The Breast Cancer Risk Assessment Tool (the Gail model) was designed by researchers at the National Cancer Institute and the National Surgical Adjuvant Breast and Bowel Project as a tool for health care providers. The tool calculates a woman's risk of developing breast cancer within the next five years and within her lifetime (up to age 90). It takes into account seven key risk factors for breast cancer.
- Age at first period
- Age at the time of the birth of her first child (or has not given birth)
- Family history of breast cancer (mother, sister or daughter)
- Number of past breast biopsies
- Number of breast biopsies showing atypical hyperplasia
Women with a five-year risk of 1.67 percent or higher are classified as "high-risk". This score (a five-year risk of 1.67 percent or higher) is the cut-off for the FDA guidelines on tamoxifen and raloxifene use for breast cancer risk reduction.
Learn more about risk-lowering drugs.
Individual risk versus group risk
The Breast Cancer Risk Assessment Tool cannot predict whether or not you will develop breast cancer. It does not calculate individual breast cancer risk, but rather the average risk for a group of women with similar risk factors. Thus, it is not clear what this risk means for any one woman.
Say the tool gives you a five-year risk of 1.7 percent. This means the tool estimates that 1.7 percent of women who have risk factors similar to your own will develop breast cancer over the next five years. But, the tool cannot predict which of these women will go on to be diagnosed.
How to interpret your estimated risk
The Breast Cancer Risk Assessment Tool was designed to be used by health care providers. So, if you use the tool on your own, it may be hard to understand what the risk it calculates means for you. If you have questions about your risk of breast cancer, talk to your health care provider.
Limitations of the Breast Cancer Risk Assessment Tool
The Breast Cancer Risk Assessment Tool does not give a good estimate of risk in some women including those with :
The original model was based on data from white women. Recently, the model was updated to estimate risk for:
- African American women using data from the Contraceptive and Reproductive Experiences (CARE) Study
- Asian American and Pacific Islander women using data from the Asian American Breast Cancer Study (AABCS)
However, it's still not clear how well the model works in other racial/ethnic populations.
The Breast Cancer Risk Assessment Tool also does not use all the known (established) risk factors for breast cancer to assess risk.
Even with its current limitations, the Breast Cancer Risk Assessment Tool can be useful. However, it is not a perfect predictor of individual risk. The model can estimate your risk, but it cannot tell whether or not you will get breast cancer.
Visit the National Cancer Institute website to access the Breast Cancer Risk Assessment Tool.
Looking ahead at risk assessment
As research in risk assessment grows, tools like the Breast Cancer Risk Assessment Tool will become better able to predict risk in large groups of women. Learn about new methods of estimating risk.