> Family History of Breast, Ovarian or Prostate Cancer
Family history is an important risk factor for breast cancer. Having one immediate female relative (mother, sister or daughter) with breast cancer almost doubles a woman's chance of getting breast cancer compared to a woman without a family history [41-43]. If a woman has more than one immediate female relative with a history of breast cancer, her risk is about three to four times higher than that of a woman without a family history [41-43]. Learn about the risk related to having a male relative with breast cancer below.
In general, the younger her relative was when she was diagnosed, the greater a woman's chance of getting breast cancer [43]. A woman whose mother was diagnosed with breast cancer before age 50 has about twice the risk of a woman without immediate family members with breast cancer [43]. For a woman whose mother was diagnosed after age 50, the increase in risk isn't as great.
Male family members with a history of cancer and risk of breast cancer
When talking about family history, it's also important to consider the men in your family. A history of breast cancer in a close male relative (father, brother, uncle), though rare, can increase breast cancer risk. A history of prostate cancer in one or more immediate relatives (father or brother) may also increase risk, especially if cancer was found at an early age [44-46]. Exactly why a family history of prostate cancer may increase breast cancer risk isn't known yet, though the risk of both cancers is impacted by blood hormone levels. Certain inherited gene mutations can also increase risk of these cancers (see below).
Inherited gene mutations and risk of breast cancer
While the increase in breast cancer risk linked to family history may be due to family lifestyle factors, it can also be linked to genetic mutations that can increase risk. This is often the case in families with a strong family history of breast cancer. Such families may have more than one immediate relative (mother or sister) 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 genetic mutation. Learn more about inherited genetic mutations and breast cancer risk.
People with limited information on family medical history
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 family history details. Talking with a health care provider about other risk factors can help you learn what you can do to reduce your risk if you do not have family medical information.
Updated 11/09/09
