Breast Cancer Risks
A family history of breast cancer and other factors increase the risk of breast cancer.
Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. Talk to your doctor if you think you may be at risk for breast cancer.
Risk factors for breast cancer include the following:
- A personal history of invasive breast cancer, ductal carcinoma in situ (DCIS), or lobular carcinoma in situ (LCIS).
- A personal history of benign (noncancer) breast disease.
- A family history of breast cancer in a first-degree relative (mother, daughter, or sister).
- Inherited changes in the BRCA1 and BRCA2 genes or in other genes that increase the risk of breast cancer.
- Breast tissue that is dense on a mammogram.
- Exposure of breast tissue to estrogen made by the body:
- Menstruating at an early age.
- Older age at first birth or never having given birth.
- Starting menopause at a later age.
- Taking hormones such as estrogen combined with progestin for symptoms of menopause
- Treatment with radiation therapy to the breast/chest.
- Drinking alcohol.
- Being white.
Older age is the main risk factor for most cancers. The chance of getting cancer increases as you get older.
Breast cancer is sometimes caused by inherited gene mutations (changes).
The genes in cells carry the hereditary information that is received from a person’s parents. Hereditary breast cancer makes up about 5% to 10% of all breast cancer. Some mutated genes related to breast cancer are more common in certain ethnic groups.
Women who have certain gene mutations, such as a BRCA1 or BRCA2 mutation, have an increased risk of breast cancer. These women also have an increased risk of ovarian cancer, and may have an increased risk of other cancers. Men who have a mutated gene related to breast cancer also have an increased risk of breast cancer.
There are tests that can detect (find) mutated genes. These genetic tests are sometimes done for members of families with a high risk of cancer.
The use of certain medicines and other factors decrease the risk of breast cancer.
Anything that decreases your chance of getting a disease is called a protective factor.
Protective factors for breast cancer include the following:
- Taking any of the following:
- Estrogen-only hormone therapy after a hysterectomy.
- Selective estrogen receptor modulators (SERMs).
- Aromatase inhibitors.
- Less exposure of breast tissue to estrogen made by the body:
- Early pregnancy.
- Getting enough exercise.
- Having any of the following procedures:
- Risk-reducing mastectomy.
- Risk-reducing oophorectomy.
- Ovarian ablation.
Reference: National Cancer Institute
Last updated: February 9, 2016.