A family history of certain types of cancer can increase your risk of breast cancer. This increased risk may be due to genetic factors (known and unknown), shared lifestyle factors or other family traits.
Most women with breast cancer do not have a family history of the disease. Only about 13 percent of women diagnosed have a first-degree female relative (mother, sister or daughter) with breast cancer .
A woman who has one first-degree female relative with breast cancer has almost twice the risk of a woman without a family history [6,84-85]. If she has more than one first-degree female relative with a history of breast cancer, her risk is about three to four times higher [6,84-85].
In general, the younger the relative was when she was diagnosed, the greater a woman's chance of getting breast cancer . For example, a woman whose mother was diagnosed with breast cancer before age 50 has about twice the risk of a woman without a family history . For a woman whose mother was diagnosed after age 50, the increase in risk isn't as great.
When talking about family history, it's important to consider both sides of your family. A history of breast cancer in a close male relative (father, brother or uncle) increases your risk of breast cancer .
A history of prostate cancer in one or more first-degree relatives (father or brother) may also increase a woman's risk of breast cancer, especially if the prostate cancer was found at a young age [86-88]. At this time, we don't know exactly why a family history of prostate cancer might increase breast cancer risk though certain inherited gene mutations can increase risk of these cancers (see below).
The breast cancer risk linked to family history may be due to shared lifestyle factors or gene mutations that increase risk. Families with a strong family history of breast cancer often carry inherited gene mutations. Such families may have more than one first-degree relative (mother, sister or daughter) with breast cancer, a single female relative diagnosed at an early age or a male relative with breast cancer. Family history of ovarian cancer may also be related to an inherited gene mutation.
Inherited gene mutations account for only five to 10 percent of all breast cancers diagnosed in women in the U.S. [4,26].
Learn more about inherited gene mutations and breast cancer risk.
For a summary of research studies on inherited genetic mutations and breast cancer, visit the Breast Cancer Research section.
There are special breast cancer screening guidelines for women with a strong family history of breast or ovarian cancer (for example, two or more first-degree relatives with breast cancer or two or more with ovarian cancer). If you have a strong family history, the National Comprehensive Cancer Network and the American Cancer Society recommend, starting at age 30, you get a [89-90]:
This medical care helps ensure that if breast cancer does develop, it is caught early when the chances of survival are highest.
Learn more about breast cancer screening recommendations for women at higher risk.
Learn more about breast cancer screening recommendations for men at higher risk due to an inherited gene mutation or strong family history.
If you have a family history of breast or other type of cancer, your health care provider can help you understand how this impacts your risk of breast cancer.
The Office of the Surgeon General and the National Human Genome Research Institute (part of the National Institutes of Health, Department of Health and Human Services) created an online tool called “My Family Health Portrait” that you can use to create a chart of your family’s health history. This chart may be useful in discussions with your provider about your family history of breast cancer and/or other health conditions.
Learn more about talking to your health care provider.
Some people may not know their family medical history. Risk assessment tools such as the Breast Cancer Risk Assessment Tool (Gail model) can estimate your breast cancer risk without this information. However, it will be less accurate without your family history details.
Talking with your health care provider about other risk factors for breast cancer can help you learn more about your risk if you do not have information on your family medical history.
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