The following have been identified as Breast Cancer Risk Factors You Can’t Control
Gender. Being a woman is the most significant risk factor for developing breast cancer. Although men can get breast cancer, too, women’s breast cells are constantly changing and growing, mainly due to the activity of the female hormones estrogen and progesterone. This activity puts them at much greater risk for breast cancer.
Age. Simply growing older is the second biggest risk factor for breast cancer. From age 30 to 39, the risk is 1 in 233, or .43%. That jumps to 1 in 27, or almost 4%, by the time you are in your 60s.
Family history of breast cancer. If you have a first-degree relative (mother, daughter, sister) who has had breast cancer, or you have multiple relatives affected by breast or ovarian cancer (especially before they turned age 50), you could be at higher risk of getting breast cancer.
Personal history of breast cancer. If you have already been diagnosed with breast cancer, your risk of developing it again, either in the same breast or the other breast, is higher than if you never had the disease.
Race. White women are slightly more likely to develop breast cancer than are African American women. Asian, Hispanic, and Native American women have a lower risk of developing and dying from breast cancer.
Radiation therapy to the chest. Having radiation therapy to the chest area as a child or young adult as treatment for another cancer significantly increases breast cancer risk. The increase in risk seems to be highest if the radiation was given while the breasts were still developing (during the teen years).
Breast cellular changes. Unusual changes in breast cells found during a breast biopsy (removal of suspicious tissue for examination under a microscope) can be a risk factor for developing breast cancer. These changes include overgrowth of cells (called hyperplasia) or abnormal (atypical) appearance.
Exposure to estrogen. Because the female hormone estrogen stimulates breast cell growth, exposure to estrogen over long periods of time, without any breaks, can increase the risk of breast cancer. Some of these risk factors are not under your control, such as:
- starting menstruation (monthly periods) at a young age (before age 12)
- going through menopause (end of monthly cycles) at a late age (after 55)
- exposure to estrogens in the environment (such as hormones in meat or pesticides such as DDT, which produce estrogen-like substances when broken down by the body)
Pregnancy and breastfeeding. Pregnancy and breastfeeding reduce the overall number of menstrual cycles in a woman’s lifetime, and this appears to reduce future breast cancer risk. Women who have never had a full-term pregnancy, or had their first full-term pregnancy after age 30, have an increased risk of breast cancer. For women who do have children, breastfeeding may slightly lower their breast cancer risk, especially if they continue breastfeeding for 1 1/2 to 2 years. For many women, however, breastfeeding for this long is neither possible nor practical.
DES exposure. Women who took a medication called diethylstilbestrol (DES), used to prevent miscarriage from the 1940s through the 1960s, have a slightly increased risk of breast cancer. Women whose mothers took DES during pregnancy may have a higher risk of breast cancer as well.