Breast cancer happens when cells in the breast begin to grow and divide out of control. Aside from some types of skin cancers, it’s the most common cancer affecting women in the United States.

According to the American Cancer Society (ACS), a woman’s average lifetime risk of developing breast cancer is about 13 percent. This translates to a 1 in 8 chance of getting breast cancer.

However, for some, breast cancer risk is increased. These individuals are said to be at high risk of breast cancer.

Learn what being at a high risk for breast cancer means, what factors put you at high risk, and recommendations for early cancer detection in high-risk individuals.

What does it mean to be at a high risk for breast cancer?

Being at a high risk for breast cancer means that you have an increased likelihood of developing breast cancer over the course of your lifetime. If you are classified as having a high risk for breast cancer, it doesn’t mean that you’ll absolutely develop breast cancer sometime in the future. It means that you’re at a high risk for the condition compared to the general population.

There’s currently no standardized approach to assessing an individual’s breast cancer risk. However, there are several tools that help doctors identify those at a high risk of breast cancer.

Breast cancer risk assessment tools are heavily based on your personal and family history. However, they do take other factors into account as well. A few examples of commonly used tools include the:

  • Breast Cancer Risk Assessment Tool (BCRAT), also called the Gail model
  • International Breast Cancer Intervention Study (IBIS) risk calculator, also called the Tyrer-Cuzick model
  • Claus model, based off the Cancer and Steroid Hormone Study

Risk assessment tools provide a variety of measurements. These can include 5-year risk, 10-year risk, and lifetime risk.

What’s considered high risk can vary by location. In the United States, people with an estimated 5-year risk of 1.67 percent or higher are typically considered high risk.

Doctors consider several factors to determine if you’re at a high risk of breast cancer. All of these factors, except for pregnancy history and radiation exposure, are things you cannot change:

  • Family history: If you’ve had one or more close relatives, such as parents, siblings, or children with breast cancer, your risk increases.
  • Genetics: Having inherited gene mutations that are associated with family cancer syndromes, particularly those in BRCA1 or BRCA2, significantly boost your risk of developing breast cancer.
  • Age: The risk of breast cancer goes up as you get older.
  • Personal history: A personal history of certain breast conditions raises your breast cancer risk. These include:
  • Menstrual and pregnancy history: Starting your period at an early age, going through menopause later, or not having children are associated with an increased risk of breast cancer.
  • Breast density: Having dense breasts on a mammogram raises your breast cancer risk.
  • Radiation exposure: If you received radiation therapy to your chest area between the ages of 10 and 30, your breast cancer risk is higher.

Remember that there’s no standardized way to determine breast cancer risk. While breast cancer risk assessment tools are important in helping to estimate risk, they typically don’t take all of the factors above into account.

For example, the BCRAT tool asks for information on age, family history of breast cancer, and menstrual and pregnancy history. However, it doesn’t use information on genetics, personal history of breast conditions, or radiation exposure.

Because of this, in addition to the results of one or more risk assessment tools, your doctor will also evaluate other details from your personal history, family history, and lifestyle to better assess your breast cancer risk.

Genetic testing

Genetic testing can help to detect certain mutations associated with breast cancer. Consider genetic testing if you have:

  • a strong family history of breast cancer
  • a close family member with a known mutation that increases breast cancer risk
  • a personal or family history of other cancers associated with BRCA1 or BRCA2 mutations, such as ovarian cancer or pancreatic cancer

In these situations, knowing your inherited level of risk is important. That’s because it can help to inform screening and preventive care decisions going forward.

Those at a high risk of breast cancer can benefit from additional monitoring or screening. This can help to detect and begin treatment for breast cancer early.

Doctors may also spread out screening tests by 6 months to increase surveillance to two times a year, rather than once a year. For example, they may recommend a mammogram in January and an MRI in June.

Currently, the ACS recommends that the following people receive both a mammogram and a breast MRI each year, often starting at age 30:

  • those with a lifetime risk of breast cancer of 20 to 25 percent or more based on risk assessment tools
  • individuals with a known mutation in BRCA1 or BRCA2 or those who have a close relative with a known BRCA1 or BRCA2 mutation
  • people who received radiation therapy to their chest area between the ages of 10 and 30
  • those with a personal or family history of the following family cancer syndromes:
    • Li-Fraumeni syndrome
    • Cowden syndrome
    • Bannayan-Riley-Ruvalcaba syndrome

There are benefits to using both types of screening technology. Although a breast MRI is more likely to find cancer, it may miss changes that a mammogram would detect.

Additionally, the ACS states that there’s currently not enough evidence to recommend a yearly breast MRI for people with dense breasts or a history of breast conditions like DCIS, LCIS, ADH, and ALH.

If this applies to you, talk to your doctor about when to begin breast cancer screening and whether or not a breast MRI should be included. They can take your other risk factors into account to determine the best course of action.

Preventive steps you can take

If you’re at a high risk of breast cancer, there are preventive steps that you can take. Talk to your doctor about which ones may be appropriate for your individual situation:

  • Medications: There are medications, such as tamoxifen and raloxifene, that can help to lower your risk of developing breast cancer.
  • Surgery: A prophylactic mastectomy is surgery to remove one or both breasts in order to reduce the chances of breast cancer.
  • Lifestyle changes: Various lifestyle changes may also help to lessen your breast cancer risk. These include:
    • maintaining a healthy BMI

People with a high risk of breast cancer have an increased risk of developing breast cancer in comparison to an average-risk individual. There are various risk assessment tools that can help to estimate breast cancer risk.

Some of the most important factors in determining if a person is at a high risk of breast cancer are family history and genetics. Other factors, such as age, a history of certain breast conditions, and breast density also play a role.

Individuals at a high risk of breast cancer can benefit from yearly mammograms and breast MRIs to help detect breast cancer early. If you’re concerned that you may be at a high risk of breast cancer, be sure to discuss this with your doctor.