A risk factor is anything that increases or affects your chances of getting a disease. For breast cancer:

  • Gender plays the greatest role in determining who is at risk, because women are at greater risk of developing the disease than men.
  • Age also is a factor, and as a woman’s age increases, so does her risk of developing breast cancer.
  • Women with a personal history of breast cancer (already had cancer in one breast) are at highest risk of developing cancer in the other breast.

Other factors include:

  • BRCA1 or BRCA2 genes
  • Heredity
  • Environmental substances (such as asbestos, radon and overexposure to ultraviolet rays)
  • Female hormones: early menstruation, no pregnancies, late menopause, and estrogen replacement therapy
  • Ethnicity
  • Excessive alcohol intake
  • Tobacco intake use
  • Obesity


Healthy breast cancer susceptibility genes, also known as BRCA1 and BRCA2, help prevent breast cancer. A small number of women carry a mutation or defect of these genes, which greatly increases the risk of developing breast cancer, as well as ovarian cancer. While breast cancer isn't always a hereditary condition, the mutation of BRCA1 or BRCA2 does run in families.

  • About 5 to 10 percent of women with breast cancer have BRCA1 or BRCA2 mutations.
  • Between 1 in 400 and 1 in 800 women in the U.S. are BRCA1 or BRCA2 carriers.
  • Men who carry a BRCA gene mutation have an increased risk of developing breast and prostate cancer, as well as other types of cancer.

You may carry this genetic mutation if any of the following characteristics apply to you:

  • You developed breast cancer before age 50
  • Your mother, sister, or daughter developed breast or ovarian cancer before age 50
  • Your mother, sister, or daughter developed ovarian cancer
  • Any female blood relative developed both breast and ovarian cancer
  • You or any female blood relative developed breast cancer in both breasts
  • You are of Ashkenazi Jewish descent
  • Any male blood relative developed breast cancer

If you have a family history of breast cancer, you can consider taking a genetic test to determine if you carry the BRCA-1 or BRCA-2 genetic mutations. If you do test positive for the BRCA mutation, you can consider the following options:

  • Close monitoring: You can closely monitor your breast health with frequent digital mammograms, breast MRI, and clinical breast exams every 6 months to detect abnormalities as early as possible
  • Prophylactic surgery: You can choose to have one or both of your breasts and/or your ovaries surgically removed to greatly reduce your chances of developing cancer.
  • Lifestyle choices: Make healthy lifestyle choices to lower your risk of developing cancer. These choices include maintaining a healthy weight and nutritious, low-fat diet, exercising, and limiting alcohol intake.
  • Chemo prevention: Your doctor may recommend taking tamoxifen to reduce your risk of breast cancer.


The majority of breast cancer is not hereditary, but it can affect several people in the same family. A family history of breast cancer means you have two or more close relatives who developed breast and/or ovarian cancer, especially if the cancer appeared before age 50.

If one of your female relatives develops breast cancer, your own risk for developing the condition doubles compared to someone without a family history. That risk goes up even further if more than one close female relative develops breast cancer at a young age.

Breast cancer risk can be inherited from either your mother's or your father's side of the family, so it is important to know your full family history.

Radiation Exposure

Research demonstrates that women exposed to high doses of radiation during childhood have an increased risk of developing breast cancer. Examples of this kind of exposure include radiation therapy for childhood cancer or Hodgkin's disease and frequent X-rays for childhood diseases.

Your risk for breast cancer increases depending on how much radiation you were exposed to and how young you were at the time of your exposure. If you were exposed to radiation, you should monitor your breast health closely and discuss with your MedStar Health doctor whether you will need an MRI of your breast.

Location Information

For a physician referral, please call



MedStar Harbor Hospital
Outpatient Center
3001 South Hanover St.
Baltimore, MD 21225

Cancer Care Specialists