A risk factor is something that raises your chances of getting a health problem.
You can have breast cancer with or without the factors listed below. The more you have, the greater your chances of getting it. If you have many risk factors, ask your doctor what you can to do lower your risk.
The most common risk factors, gender and age, cannot be changed. Breast cancer is far more common in women, but men can also have it. Breast cancer risk increases with age. Most women with breast cancer are over 50 years old, but it can be found at any age.
Breast cancer risk is also higher for:
About 15 of 100 women with breast cancer have a family history. The amount of risk depends on how close the relations are to you and how many of them have breast cancer. The risk is highest and doubled if you have a parent, sister, or child with breast cancer.
Having male relatives with breast cancer also makes your risk higher, but the risk levels are not as clear.
Families with a high risk of breast cancer may want to think about genetic testing. This will help you know if there are any known genetic factors causing a higher risk. Genetic changes are in the DNA. Some of these changes allow cancer to start and grow. The DNA comes from your parents.
The 2 most common come from the BRCA1 and BRCA2 genes. They are linked to the largest increase in lifetime risk. Women with the BRCA1 or BRCA2 genes have a higher risk of:
- Breast cancer at an earlier age
- Breast cancer in both breasts
- Ovarian cancer
There are other genes linked to breast cancer, but the BRCA genes are by far the most common cause of family-related breast cancer.
Current or past health problems are linked to a higher risk of breast cancer. These are:
- Breast cancer or other problems with the breasts
- Breasts with dense tissue—there is more lobular and ductal tissue than fatty tissue
- Radiation therapy to the breast before the age 30 years
- Getting pregnant after the age of 30 years
- Not getting pregnant at all
- Not breastfeeding
- Excess weight, mainly after menopause
- Higher exposure to estrogen, which includes:
- First monthly period before age 13 years
- Menopause after age 51 years
- Long-term use of hormone replacement therapy (HRT), mainly after menopause
- Transgender women receiving hormone treatments
- Prior biopsy results showing lobular carcinoma in situ (LCIS) or a star-shaped mass in the breast
Some habits can make the risk of breast cancer higher such as:
- 3 or more alcoholic drinks a day
- Inactive lifestyle
- Use of birth control pills or shots
- High intake of red meat
In the US, White, Hawaiian, and Black women have the highest rates of breast cancer. The lowest rates occur among Korean, American Indian, and Vietnamese women.
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Breast cancer. Merck Manual Professional Version website. Available at: https://www.merckmanuals.com/professional/gynecology-and-obstetrics/breast-disorders/breast-cancer. Updated January 2018. Accessed March 11, 2019.
Breast cancer risk and prevention. American Cancer Society website. Available at: https://www.cancer.org/cancer/breast-cancer/risk-and-prevention.html. Accessed March 11, 2019.
General information about breast cancer. National Cancer Institute website. Available at: https://www.cancer.gov/types/breast/patient/breast-treatment-pdq#_125. Updated February 6, 2019. Accessed March 11, 2019.
Risk factors for breast cancer. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T901178/Risk-factors-for-breast-cancer. Updated June 1, 2018. Accessed March 11, 2019.
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Last reviewed December 2018 by EBSCO Medical Review Board Mohei Abouzied, MD, FACP Last Updated: 7/10/2019