The Who, What, Where, When and Sometimes, Why.

Estimating Breast Cancer Risk

To estimate your risk of breast cancer, your health care provider looks at:

  • How many risk factors you have
  • How much those factors increase risk

A few factors, such as having a BRCA1 or BRCA2 inherited gene mutation, increase breast cancer risk a lot. However, most known factors have a small or modest effect on risk.

Exactly which risk factors should be used to estimate breast cancer risk is still under study.

The Breast Cancer Risk Assessment Tool (the Gail Model)

The Breast Cancer Risk Assessment Tool (the Gail model) is often used by health care providers to estimate risk. Although the tool can estimate your risk, it can’t tell whether or not you’ll get breast cancer.

The tool calculates a woman’s risk of developing breast cancer within the next 5 years and within her lifetime (up to age 90).

It uses 7 key risk factors for breast cancer.

  • Age
  • Age at first period
  • Age at the time of the birth of a 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
  • Race/ethnicity

Women with a 5-year risk of 1.67 percent or higher are classified as “high-risk.” A 5-year risk of 1.67 percent or higher is the FDA guideline for taking a risk-lowering drug to reduce breast cancer risk.

Individual risk versus group risk

The Breast Cancer Risk Assessment Tool can’t predict whether or not you’ll get breast cancer. It doesn’t calculate an individual woman’s breast cancer risk.

Instead, the tool gives the average risk of breast cancer for a group of women with similar risk factors. It’s not clear what this risk means for any one woman.

Say the tool gives you a 5-year risk of one percent. This means the tool estimates one percent of women who have risk factors similar to yours will develop breast cancer over the next 5 years. However, the tool can’t predict which of these women will get breast cancer.

How to interpret your estimated breast cancer 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 the results and use the information to make decisions about your care.

If you have questions about your breast cancer risk, talk with your health care provider.

Limits of the Breast Cancer Risk Assessment Tool

The Breast Cancer Risk Assessment Tool does not use all the known (established) risk factors for breast cancer to assess risk.

The tool also does not give a good risk estimate for some women, including those with a [1]:

The original model was based on data from white women. The tool can now estimate risk for:

  • Black women, using data from the Contraceptive and Reproductive Experiences (CARE) Study
  • Asian and Pacific Islander women in the U.S., using data from the Asian American Breast Cancer Study
  • Hispanic women, using data from the San Francisco Bay Area Breast Cancer Study, the California Cancer Registry and the California Surveillance, Epidemiology, and End Results (SEER) Program 

The model does not work as well for other racial and ethnic groups.

Visit the National Cancer Institute website to learn more about the Breast Cancer Risk Assessment Tool.

Other breast cancer risk assessment tools

Some tools, such as the Claus model, use family history to estimate breast cancer risk. Such tools can be used for women who have one or more relatives with breast cancer, or one or more relatives with ovarian cancer.

Other tools, such as IBIS (uses the Tyrer-Cuzik model) and BOADICEA, use family history and other factors to estimate breast cancer risk.

Looking ahead at breast cancer risk assessment

As research in risk assessment grows, tools like the Breast Cancer Risk Assessment Tool will be better able to predict risk in large groups of women.

Talking with your health care provider about your risk of breast cancer

If you have questions about your breast cancer risk, talk with your doctor, nurse or other health care provider.

Your family health history plays a role in your breast cancer risk. Before you meet with your health care provider, it’s helpful to collect information about your family health history.

Information on any cancers diagnosed in your family (and the ages when people were first diagnosed) will be helpful in assessing your breast cancer risk.

If you are considering genetic testing to learn if a family history of cancer is due to an inherited gene mutation related to cancer risk, talk with your health care provider or a genetic counselor. They can help you decide if genetic testing is right for you and your family.

Susan G. Komen®‘s My Family Health History Tool

My Family Health History tool is a web-based tool that makes it easy for you to record and organize your family health history. It helps you gather information that will be useful as you talk with your doctor or genetic counselor.

Updated 02/24/21

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