Assessing Your Genetic Risk

Expert Quote

“Testing is primarily useful when a mutation is identified in a cancer patient. In that case, other family members can have reliable results.”

Generosa Grana M.D., F.A.C.P.

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Many women who seek genetic testing do so because they believe their breast cancer risk is higher than it really is. Often, they want to know if they have an abnormal breast cancer gene because they or a family member has cancer. Women are particularly anxious if the cancer happens at a young age.

Education is the first step in genetic risk assessment. The concerned individuals or their family members need information about breast cancer and breast cancer risk. Discussions should include information about the role of genetics in breast cancer, a description of the testing process, and the benefits and drawbacks of genetic testing.

If you decide to proceed with genetic risk assessment, a genetic counselor or other health care professional trained in breast cancer genetics will help you prepare a family tree. This chart, also known as a pedigree, lists members of each generation of your biological family, with all available health and disease information. Ideally, this family tree should go back at least three generations and should include the type of cancer each relative has had, as well as the person's age at diagnosis. But in reality, most people don't have much information before their grandparents' generation.

After the family tree has been constructed, the genetic counselor analyzes the pattern of breast cancer in the family. Your family's pedigree can be categorized in one of three ways:

• Sporadic. This means your personal or family history of breast cancer doesn't follow any regular pattern of inheritance. Instead, breast cancer appears in a scattered, isolated way. About 70% of all women with breast cancer have a sporadic family pedigree.
• Familial. This means there may be a strong family history of breast cancer, but there's no well-defined pattern suggesting that the breast cancer was passed genetically from one generation to another. About 20% of all women with breast cancer have a familial breast cancer pedigree.
• Hereditary. This means there is a compelling family history, including multiple blood relatives with breast and/or ovarian cancer. That pattern strongly suggests an inherited form of the disease. Heredity accounts for about 10% of all breast cancers, and abnormal BRCA1 and BRCA2 genes explain a large number of these cancers. But other genes that have not been discovered yet are probably also involved.

Judging the need for genetic testing

Experts generally agree that women in the first category of family history — sporadic — will not benefit from the gene test. Those in the second category — familial — are at moderate risk and will probably not be encouraged to get the test.

If you fall into the third — hereditary — category, you may decide to go ahead with the breast cancer gene test.

For more information on genetic testing, counseling, and support visit the FORCE (Facing Our Risk of Cancer Empowered) website.