Risks of Breast Cancer

The discussion around the risk for developing breast cancer tends to focus on the BRCA gene, but in actuality only 5 percent to 10 percent of breast cancer diagnoses are due to hereditary influences. There are a vast number of factors that help identify who is at risk for breast cancer, and while certain factors may be beyond your control, some are behaviors you are able to change. Taking the time to educate yourself about the risks is the first step in reformed behavior. The following categories give an overview of the primary risk factors and behaviors associated with breast cancer.

Factors Beyond Your Control



  • As a person ages there is a greater chance of genetic damage, making age a significant factor in developing breast cancer. The risk of diagnosis increases from a .44 percent chance of diagnosis in one's 20s to a 3.88 percent chance in one's 70s.


  • Less than 1 percent of breast cancer patients are men. Women are at a significantly greater risk, but men do develop breast cancer. Out of 100,000 men, 1.3 will be diagnosed with breast cancer, but typically are diagnosed at a later stage, possibly because they are less likely to report their symptoms.

Race and ethnicity:

  • Overall, Caucasians are more likely to acquire breast cancer; however, African-Americans are more likely to die from breast cancer. This is due to more aggressive diagnoses of cancers, or lower rates of early detection.
  • There is a particularly heightened risk for those who are Ashkenazi Jewish (Eastern Jewish).

Family History

Women with first-degree female relatives (mom, sister, or daughter) diagnosed with breast cancer are at double the risk for developing breast cancer. Your risk for diagnosis increases as the number of diagnosed, first-degree female relatives increases. Women with two first-degree female relatives diagnosed are at five times the risk.


There is increased risk for those with:

  • BRCA1, BRCA2, and other genetic abnormalities. BRCA gene mutations account for 10 percent of all breast cancers.
  • Any blood relation diagnosed with breast cancer before age 50.
  • Blood relations who have any kind of gland-related cancers.
  • Male relatives with breast cancer at any age.

Personal History of Breast Cancer or Other Cancers

Breast Cancer survivors are three to four times more likely to develop a new cancer.

Radiation therapy, which can be used to treat various health concerns ranging from acne to serious illnesses like lymphoma, significantly raises the risk of developing breast cancer when performed before age 30.

Breast Density and Conditions

Dense breasts increase the cancer risk by six times and make mammograms less effective. Breast density is impossible to predict before a mammogram. Over time, breasts become less dense.

Benign breast conditions also cause an increased risk. For those with duct or lobule growths, such as those with atypical ductal or lobular hyperplasia, the risk is four to five times greater. Conditions like ductal hyperplasia, complex fibroadenoma, sclerosing adenosis, radial scar, and papilloma/papillomatosis double the risk for cancer.

Lobular carcinoma in situ (LCIS) increases the risk of invasive cancer by seven to 11 times.

Childbearing and Menstrual Cycle

Menstrual span:

  • Menstruation earlier than age 12 or later than age 55 produces greater risk for developing breast cancer, as it expands the duration of time when breast cells are most vulnerable.


  • Until a first full-term pregnancy, breast cells are immature and more susceptible to hormones, hormone disrupters, and environmental factors.
  • DES (Diethylstilbestrol) is a synthetic estrogen that was administered to pregnant women at risk of miscarriage from the 1940s to the 1960s, and both mothers and daughters who were exposed to DES have an increased risk of developing breast cancer.


  • Studies indicate that breastfeeding lowers the risk of breast cancer, particularly if breastfeeding occurs for 12 months or more. It is not quite clear if this is due to decreased menstrual cycles, amount of time spent breastfeeding, or a healthier lifestyle.

Controllable Factors


Weight and exercise:

  • Those with a BMI of 25 or higher are more likely to have breast cancer, or to have breast cancer recur, as fat cells produce estrogen.
  • Studies concur that 30 to 60 minutes per day of moderate to high-intensity physical activity lowers the risk of breast cancer. This effect is most pronounced in post-menopausal women.


  • Diet is actually thought to be partly responsible for 30 percent to 40 percent of all cancers. Eating low-fat, plant-based, pesticide-free healthy food, especially those that boost immunity, can help lower risk. Eat the Clean 15 and avoid the Dirty Dozen
  • Food that is grilled, blackened, barbequed, or smoked contains HCAs (heterocyclic amines), and PAHs (polycyclic aromatic hydrocarbons), which have been linked to breast cancer. Women who eat a lot of grilled, barbecued, and smoked meats, combined with few fruits and vegetables, are placing themselves at higher risk.

Alcohol and smoking:

  • With three or more drinks a week, there is a 15 percent increase in risk. Each additional drink increases risk by 10 percent.
  • Exposure to carcinogens is a clear risk factor, although the data specific to breast cancer is inconclusive. The carcinogens are most harmful to the individual smoking, but it's important to note that "there is no safe level of exposure to secondhand smoke."

Hormones and Vitamins

Vitamin D and light exposure:

  • The immunity function of Vitamin D helps lower the risk of developing breast cancer. Vitamin D is best gained through sunlight or supplements. As documented, high sun exposure increases the risk of acquiring skin cancer, and habits like applying sunscreen lower vitamin D levels. Therefore, it is worth noting that short periods (15 minutes, three times a week, for example) of direct peak sun can provide the daily-recommended dose of vitamin D.
  • Excessive external lighting (street lights) at night or working night shifts increase the risk of breast cancer, possibly due to lowered melatonin levels.

Hormone replacement therapy

  • Women experiencing moderate to severe menopausal symptoms may be treated with hormone therapy. Estrogen-only replacements create a greater risk for developing breast cancer, when used for 10 or more years. Estrogen/progesterone combination therapy increases risk by 75 percent, and the cancers identified are usually at a more advanced stage with greater likelihood of death. Two years after cessation of the combination therapy, risk returns to a normal range.

The list of factors that affect your risk can feel overwhelming, but the best way to minimize your risk for breast cancer is to maintain open communication with your primary care provider. Depending on your medical history and lifestyle, there are options to minimize your risk that your primary care provider may recommend. These range from increased screenings to preventive surgeries, such as mastectomy or oophorectomy. Learning more about your own risks will help you identify which changes you can make that will help prevent breast cancer. While some factors may be out of your control, changes you can make can have a significant impact on your well-being.

Explore Further

Breastcancer.org has a booklet called “Think Pink, Live Green: Protect Your Breast Health.”

The National Cancer Institute has a simplified Breast Cancer Risk Assessment Tool.

Visit  The Breast Cancer Organization website.

Visit The American Cancer Society website.

Visit The Centers for Disease Control and Prevention website.