A risk factor is something that increases your chances of getting a disease or condition.
It is possible to develop breast cancer with or without the risk factors listed below. It is also important to note that breast cancer can and does occur in women with no known risk factors. Generally, the more risk factors you have the greater your likelihood of developing breast cancer. If you have a number of risk factors, ask your doctor what you can do to reduce your risk.
The most common risk factors, gender and age, cannot be changed. Breast cancer is found mainly in women though it can also develop in men. While breast cancer can be found at any age, the risk increases with age. The majority of women diagnosed with breast cancer are over 50 years old.
Other factors that may increase your chance of breast cancer include:
Only about 15% of women with breast cancer have a family history of breast cancer. The risk is determined by how close the relations are and how many family members have breast cancer. For example, one first-degree relative such as a parent, sibling, or child with breast cancer can double an individual's risk of breast cancer. If there are two first-degree relatives with breast cancer, then an individual's risk is 3 times higher than average. Having one second-degree relatives such as aunts, nieces, or grandparents with breast cancer does not increase an individual's risk of breast cancer. However, having two second degree relatives with breast cancer does increase risk.
Having male relatives with breast cancer also increases the risk of developing breast cancer, but the risk levels are not as clear.
Families with a high risk of breast cancer may consider genetic testing to determine if known genetic factors are causing the increased risk. Genetic mutations are changes in specific cell DNA that allow cancer to develop. These mutations are inherited from the parent instead of developing over time. The 2 most common genetic mutations occur in BRCA1 and BRCA2 genes. They are linked to the largest increase in lifetime risk. Women with the BRCA1 or BRCA2 genes are at a higher risk for:
There are a number of other genetic mutations that are associated with breast cancer, but BRCA genes are by far the most common cause of family-related breast cancer.
Current or a history of certain medical conditions have been found to increase the risk of breast cancer. These may include:
Lifestyle factors that increase breast cancer risk include:
In the US, Caucasian, Hawaiian, and African American 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: http://www.merckmanuals.com/professional/gynecology-and-obstetrics/breast-disorders/breast-cancer. Updated May 2016. Accessed June 30, 2017.
Breast cancer risk and prevention. American Cancer Society website. Available at: https://www.cancer.org/cancer/breast-cancer/risk-and-prevention.html. Accessed June 30, 2017.
General information about breast cancer. National Cancer Institute website. Available at: https://www.cancer.gov/types/breast/patient/breast-treatment-pdq. Updated May 5, 2017. Accessed June 30, 2017.
Risk factors for breast cancer. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T901178/Risk-factors-for-breast-cancer. Updated October 28, 2016. Accessed June 30, 2017.
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Last reviewed June 2017 by EBSCO Medical Review Board Mohei Abouzied, MD, FACP Last Updated: 2/11/2016