Simply being female and getting older puts a woman at average risk for developing breast cancer. The older she is, the greater her chance of getting breast cancer. This disease is very uncommon in women under the age of 35 and most breast cancers occur in women over the age of 50. The risk is especially high for women over the age of 60. No woman should consider herself too old to need regular screening mammograms. Research has also shown that the following conditions increase a woman’s chance of getting breast cancer:
- Personal history of breast cancer.Women who have had breast cancer face an increased risk of getting breast cancer in their other breast.
- Genetic alterations. Changes in certain genes (BRCA1, BRCA2 and others) increase the risk
of breast cancer. In families in which many women have had the disease, genetic testing can sometimes show the presence of specific genetic changes that increase the risk of breast cancer. Doctors may suggest ways to try to delay or prevent breast cancer, or to improve the detection of this disease in women who have these changes in their genes.
- Family history of breast cancer. A woman’s risk for developing breast cancer increases if her mother, sister, or maternal /paternal grandparents or aunts had breast cancer, especially at a young age.
- Certain breast changes. Having a diagnosis of atypical hyperplasia or lobular carcinoma in situ
(LCIS) may increase a woman’s risk for developing cancer.
- Estrogen. Evidence suggests that the longer a woman is exposed to estrogen (estrogen made by
the body, taken as a drug, or delivered by a patch), the more likely she is to develop breast cancer. For example, the risk is somewhat increased among women who begin menstruation before age 12, experience menopause after age 50, never have children, or take hormone replacement therapy for long periods of time. Each of these factors increases the amount of time a woman’s body is exposed to estrogen. DES (diethylstilbestrol), a synthetic form of estrogen, was used between the early 1940s and 1971. Women who took DES during pregnancy to prevent certain complications are at a slightly higher risk for breast cancer. This does not appear to be the case for their daughters who were exposed to DES before birth. However, more studies are needed as these daughters enter the age range when breast cancer is more common.
- Late childbearing.Women who have their first child after about 30 have a greater chance of developing breast cancer than women who have their children at a younger age.
- Radiation therapy. Women whose breasts were exposed to radiation during radiation therapy before age 30, especially those who were treated with radiation for Hodgkin’s disease, are at an increased risk for developing breast cancer. Studies show that the younger a woman was when she received treatment, the higher her risk for developing breast cancer later in life.
- Alcohol. Some studies suggest a slightly higher risk of breast cancer among women who drink alcohol.
- Diet and dietary factors. Some evidence exists that a diet high in animal fat may increase the risk of breast cancer and a diet high in fruits and vegetables may decrease the risk.
Most of the women who develop breast cancer have none of the risk factors listed above, other than the risk that comes with growing older.