\"A woman generally will be advised to have genetic counseling if she has two or more first-degree relatives with breast or ovarian cancer or both, especially if the breast or ovarian cancer occurred before age 50,\" says Sandhya Pruthi, M.D., a breast health specialist at Mayo Clinic, Rochester, Minn. First-degree relatives are your parents, sisters, brothers and children.
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.
Other things to consider before genetic testing
Genetic testing can raise complex emotional and legal questions. Think about how testing might affect you or your health care choices. In considering genetic testing, talk with your doctor about a consultation with a genetic counselor. Discuss the following issues:
Learning your genetic profile. In weighing the risks and benefits of genetic testing, ask yourself a fundamental question. Do you really want to know the results? Consider how you might feel if you find out that you have a BRCA gene mutation.
Accuracy of the test. Current techniques don't easily allow for studying the gene in such a way that the mutation can be found - even when a BRCA mutation exists. In that case, a negative test might be falsely reassuring. Such a false-negative result means the test shows you don't have a mutated gene when in fact you do. Discuss with your doctor what negative test results might mean for you given your personal and family history of breast cancer.
Insurance aspects of genetic testing. If you've already had cancer, you may have trouble getting new health insurance - the results of your genetic testing aren't likely to affect that. However, if you haven't had cancer, and you're considering testing to see if you carry a high-risk gene, you might want to make any changes to your insurance before testing. Most states have enacted laws to ensure that your genetic information can't be used to deny you health insurance coverage, but health insurers do have some legal protections.
Limited prevention methods. No prevention method is 100% effective in preventing cancer, and some existing methods - such as preventive mastectomy - may be unacceptable to you.
Expense. Genetic testing is expensive. Testing may cost several hundred dollars if you have a family history of known mutation, for example, if a close relative has a BRCA mutation. However, comprehensive testing if you're unaware of your genetic history may cost several thousand dollars. Insurance may cover appropriate candidates for testing, but it's not always included in your insurance. Consider contacting your insurance company to see if your testing expenses will be covered.
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