Hereditary breast cancer is associated with patterns of cancer in families. Defining a family history of breast cancer is quite complex.
A family history of breast cancer is defined as having an unusually high number of close relatives with breast cancer, often at a younger age than would normally be expected. So, having one relative diagnosed with breast cancer at the age of 50 or older usually wouldn’t mean that you have a family history.
Other factors that can contribute to a family history are cases of male breast cancer, ovarian cancer, breast cancer in both breasts, or having Ashkenazi Jewish ancestry.
A family history can be classed as moderate or strong, based on the number of family members on the same side of your family with the breast cancer, how closely related they are to you, and the age they were diagnosed with the disease.
Moderate
Having a close relative (such as your mother, daughter or sister) diagnosed with breast cancer under 40, or two close family members on the same side (mother, daughter, sister, grandmother or aunt) diagnosed with breast cancer over 50, may be considered a moderate family history. This may increase your risk of developing the disease.
Strong
A strong family history means you may be at high risk of developing breast cancer.
Having two family members on the same side, such as your mother, daughter, sister, grandmother or aunt diagnosed with breast cancer under the age of 50 may be considered a strong family history. On the same side of your family, having three family members diagnosed with breast cancer before they reached 60, or four members diagnosed at any age may also indicate that you have a high risk of developing breast cancer.
Other patterns of cancer across families can also indicate increased breast cancer risk.
If you are concerned about any history of cancer in your family, speak with your GP.
Information last reviewed: 17 March 2011
