Cancer prevention is action taken to lower the chance of getting cancer. By preventing cancer, the number of new cases of cancer in a group or population is lowered. Hopefully, this will lower the number of deaths caused by cancer.
To prevent new cancers from starting, scientists look at risk factors and protective factors. Anything that increases your chance of developing cancer is called a cancer risk factor; anything that decreases your chance of developing cancer is called a cancer protective factor.
Some risk factors for cancer can be avoided, but many cannot. For example, both smoking and inheriting certain genes are risk factors for some types of cancer, but only smoking can be avoided. Regular exercise and a healthy diet may be protective factors for some types of cancer. Avoiding risk factors and increasing protective factors may lower your risk but it does not mean that you will not get cancer.
Different ways to prevent cancer are being studied, including:
- Changing lifestyle or eating habits.
- Avoiding things known to cause cancer.
- Taking medicine to treat a precancerous condition or to keep cancer from starting.
- Risk-reducing surgery.
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 or 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. This may be caused by:
- 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
- Obesity
Older age is the main risk factor for most cancers. The chance of getting cancer increases as you get older.
NCI’s Breast Cancer Risk Assessment Tool uses a woman’s risk factors to estimate her risk for breast cancer during the next five years and up to age 90. This online tool is meant to be used by a health care provider.
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. For more information, see the PDQ summary on Male Breast Cancer Treatment.
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. See the PDQ summary on Genetics of Breast and Gynecologic Cancers for more information.
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:
- Less exposure of breast tissue to estrogen made by the body. This can be a result of:
- Early pregnancy
- Breastfeeding
- Getting enough exercise
- Having any of the following procedures:
- Mastectomy to reduce the risk of cancer
- Oophorectomy to reduce the risk of cancer
- Ovarian ablation
More Information for Patients
BRCA1 and BRCA2: Cancer Risk and Genetic Testing
Surgery to Reduce the Risk of Breast Cancer
Reproductive History and Cancer Risk
Clinical Trials to Prevent Breast Cancer
More Information for Health Professionals
Genetics of Breast and Gynecologic Cancers (PDQ®)–Health Professional Version