Women with certain risk factors are more likely than others to develop breast cancer. A risk factor is something that may increase the chance of getting a disease.
Some risk factors (such as drinking alcohol) can be avoided. But most risk factors (such as having a family history of breast cancer) can't be avoided.
Studies have found the following risk factors for breast cancer:
* Age: The chance of getting breast cancer increases as you get older.
* Personal health history: Having breast cancer in one breast increases your risk of getting cancer in your other breast.
* Family health history: Your risk of breast cancer is higher if your mother, father, sister or daughter had breast cancer. The risk is even higher if your family member had breast cancer before age 50. Having other relatives (in either your mother's or father's family) with breast cancer or ovarian cancer may also increase your risk.
* Radiation therapy to the chest: Women who had radiation therapy to the chest (including the breasts) before age 30 are at an increased risk of breast cancer. Studies show that the younger a woman was when she received radiation treatment, the higher her risk of breast cancer later in life.
* Reproductive and menstrual history:
- The older a woman is when she has her first child, the greater her chance of breast cancer.
- Women who never had children are at an increased risk of breast cancer.
- Women who had their first menstrual period before age 12 are at an increased risk of breast cancer.
- Women who went through menopause after age 55 are at an increased risk of breast cancer.
- Women who take menopausal hormone therapy for many years have an increased risk of breast cancer.
* Race: In the United States, breast cancer is diagnosed more often in white women than in African-American/black, Hispanic/Latina, Asian/Pacific Islander, or American Indian/Alaska Native women.
* History of taking DES: DES was given to some pregnant women in the United States between about 1940 and 1971. (It is no longer given to pregnant women.) Women who took DES during pregnancy may have a slightly increased risk of breast cancer. The possible effects on their daughters are under study.
* Being overweight or obese after menopause: The chance of getting breast cancer after menopause is higher in women who are overweight or obese.
* Lack of physical activity: Women who are physically inactive throughout life may have an increased risk of breast cancer.
* Drinking alcohol: Studies suggest that the more alcohol a woman drinks, the greater her risk of breast cancer.
Having a risk factor does not mean that a woman will get breast cancer.