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Breast Cancer — Step 2:¬†Which Risk Factors May Apply to You? email this page to a friendemail this page
In this step, you explore how to know if any of the known risk factors for breast cancer apply to you. If you need to review the basics, check out What Are Risk Factors? and What is Risk Exposure?
Find out more:
Breast changes
My Family Health Portrait
Genetics and breast cancer Menopausal hormone use

Understanding Breast Cancer Risk Tool
Check the risk factors that apply to you to build your own list. Then go to Step 3 to learn what you can do to reduce your risk for factors in your list. After you build your list, you can print it out and take it with you to your doctor.

Breast Cancer Risk Factor

How Will I Know?

Does This Risk
Apply to Me?


The chance of getting breast cancer increases as you get older. If you are over age 60, you are at greatest risk. If you have not yet gone through menopause, your risk of breast cancer is lower than for women who have gone through menopause.

Personal history of breast cancer

If you have had breast cancer in one breast, you have an increased risk of getting it in the other breast.

Family history of breast cancer

If your mother, sister, or daughter has had breast cancer (especially before age 40), your risk is higher. Having other relatives with breast cancer (on either your mother’s side or your father’s side) may increase your risk.

Certain breast changes

Breast changes occur in almost all women. You might notice different kinds of breast changes at different times of your life. Most of these changes are not cancer. However, some changes may be signs of cancer.

Genetic alterations

Approximately 5 to 10 percent of American women who get breast cancer each year have a hereditary form of the disease. You are at increased risk for this form of the disease:

  • If your family has a history of multiple cases of breast cancer
  • If your family has a history of cases of both breast and ovarian cancer
  • If you have one or more family members with two primary cancers at different sites
  • If you are of Ashkenazi (Eastern European) Jewish background.

See Genetics and breast cancer in the blue area above to find out more.

Menstrual history

If you began to menstruate early (before age 12), you are at increased risk. If you went through menopause late (after age 55), you are at increased risk.

Radiation therapy to the chest

If you had radiation therapy to the chest (including your breasts) before age 30, you may be at increased risk. The younger you were when you received the radiation treatment, the higher your risk of breast cancer later in life.

Breast density

If you are an older woman who has dense (not fatty) tissue on a mammogram, you are at increased risk. Research has shown that women age 45 or older who have at least 75 percent dense tissue on a mammogram are at increased risk of developing breast cancer. Scientists do not completely understand the reasons for this.

DES (diethylstilbestrol)

DES is a synthetic form of estrogen that was given to some pregnant women in the United States between about 1940 and 1971. It is no longer given to pregnant women. If you took DES during pregnancy, you have a slightly increased risk of breast cancer. This does not appear to be the case for the daughters exposed to DES when their mothers were pregnant. However, as those daughters grow older, more studies of breast cancer risk are needed.

Reproductive history

The older you were when you had your first child, the greater your risk of developing breast cancer. If you have never had children, you also are at increased risk.

Hormone use (such as estrogen and progestin)

If you have used menopausal hormones (also called hormone replacement therapy or HRT)—either estrogen alone or estrogen plus progestin—for 5 or more years after menopause, you may have an increased risk of developing breast cancer.

Here are the basic facts about menopausal hormone use. They are based on the results of a large clinical trial, called the Women’s Health Initiative:

  • Estrogen plus progestin (combined therapy) increases the risk of breast cancer (as well as heart disease, stroke, and blood clots).
  • Women over age 65 who took the combined therapy doubled their risk of developing dementia.
  • There were fewer cases of hip fractures and colon cancer among women who used the combined therapy.

See Menopausal hormone use in the blue area above to find out more.

Obesity after menopause

If you are obese after menopause, you have 1.5 times the risk of developing breast cancer compared to women of a healthy weight. This risk seems to apply only to postmenopausal women who do not use menopausal hormones. Among women who use these hormones, there is no significant difference in breast cancer risk between obese women and women of a healthy weight.

Physical inactivity There is a strong correlation between lack of physical activity and obesity. A recent study from the Women’s Health Initiative found that physical activity among postmenopausal women who walked about 30 minutes per day was associated with a 20 percent reduction of breast cancer risk. However, this reduction in risk was greatest among women who were of normal weight. For these women, physical activity was associated with a 37 percent decrease in risk. The protective effect of physical activity was not found among overweight or obese women.
Alcoholic beverages Having two or more drinks each day increases your risk of getting breast cancer by about 25 percent. (A drink is defined as 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces of 80-proof liquor.)

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