Breast Cancer Risk Factors
Reproductive and Menstrual History
When it comes to breast cancer and a woman's reproductive and menstrual history:
- The older a woman is when she has her first child, the greater her chance of breast cancer
- Women who had their first menstrual period before age 12 are at an increased risk for breast cancer
- Women who went through menopause after age 55 are have an increased risk
- Women who never had children are at an increased risk of breast cancer
- Women who take menopausal hormone therapy with estrogen plus progestin after menopause also appear to have an increased risk
- Large, well-designed studies have shown no link between abortion or miscarriage and breast cancer.
Breast cancer is diagnosed more often in Caucasian women than in Latina, Asian American, or African American women.
Radiation Therapy to the Chest
Women who have had radiation therapy to the chest (including breasts) before age 30 are at an increased risk of breast cancer. This includes women treated with radiation for Hodgkin lymphoma. Studies show that the younger a woman was when she received radiation treatment, the higher her chances of getting the disease later in life.
Breast tissue may be dense or fatty. Older women whose mammograms (breast x-rays) show more dense tissue can be at an increased risk of cancer.
Taking DES (Diethylstilbestrol)
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.