Breast Cancer Risk Factors

Understanding Your Risk for Breast Cancer

Breast cancer statistics say it's the most common cancer in young adults ages 15 to 39. Every year in the U.S. alone more than 12,000 cases of breast cancer are diagnosed in adults under age 40. All young adults should be vigilant about their breast health. The information on this page will help you better understand breast cancer risk factors, manage your health, and connect to others at high risk.

Your Risk Factors

No one truly knows what causes breast cancer. So doctors use the term “risk factor” for anything that increases your chances of getting the disease. There are some risk factors you can control and others you cannot. Here's what you need to know about risk factors for breast cancer:

Risk Factors You CANNOT Control

• The fact that you are a woman
• Getting older
• Family history of breast cancer
• Having breast cancer in the past
• Chest exposure to radiation when you were a child or teenager
• First menstrual period earlier than age 12

Risk Factors You CAN Control

• Maintain a healthy weight
• Limit alcohol use
• Exercise regularly
• Have your first child before age 30, if possible
• Breastfeed, if possible

Having a risk factor—or even several—doesn’t mean you’ll definitely get a disease. It just increases your chances. It is possible for people with cancer risk factors to remain healthy all their lives. Conversely, most people who get cancer don’t have any presently known risk factors.

Family History of Breast Cancer

Family history and genetics are two risk factors for breast cancer. While researchers continue to search for the definite causes of breast cancer, some consider young women at high risk for breast cancer if they have either a strong family history of breast or ovarian cancer and/or genetic mutations associated with breast cancer.

All cancers come from genetic mutations. Usually, these happen in specific cells during a person’s life. In some cases, however, people inherit mutations that can influence cancer. When these mutations help cause breast cancer, doctors call it hereditary breast cancer.

Hereditary breast cancer may be indicated by a strong family history of breast or ovarian cancer. This could mean two or more relatives with breast or ovarian cancer, a relative with both breast and ovarian cancer, a male relative with breast cancer or a relative diagnosed at a young age with breast cancer.

Genetic Mutations

Mutations to the BRCA1 and BRCA2 (breast cancer 1 and 2) genes, that normally help control cell division, are the most common cause of hereditary breast cancer. Mutations in either BRCA1 or 2 substantially increase an individual’s risk of developing breast or ovarian cancer. Other genetic mutations may also increase the risk of breast cancer. However, they are much less common and do not raise your risk as much as BRCA1 and 2.

Non-BRCA mutations are also less studied, making it unclear what can be done if a woman has them.

Genetic counselors can help you understand your risks, your family history and the implications of getting genetic testing. Genetic testing can help you make more-informed decisions about your health, whether you are at high risk or already have breast cancer.

If you are at high risk for hereditary breast cancer, you have options for protecting yourself. Take your time and gather accurate information about these very personal decisions. Options include:

• Medicine or chemoprevention
• Preventive or prophylactic surgery to remove breasts and/or ovaries
• Surveillance with MRI or ultrasound to detect breast cancer early

If you already have breast cancer and tests show a hereditary mutation, this information can still inform and improve your healthcare decisions and breast cancer treatment plan. Your test results can also help your family members understand their risk.

Connections and More Information

If you would like to talk to young women affected by hereditary breast cancer, connect to our network of support through our Peer Mentor program.

For more information on hereditary breast cancer and tools for tracking your doctor visits and test results, download our Newly Diagnosed Navigator.

You can also:

• Connect with FORCE (Facing Our Risk of Cancer Empowered), a nonprofit for people with hereditary breast and ovarian cancer.
• Find genetic counselors on the National Cancer Institute website or through the National Society of Genetic Counselors.