What is a breast and ovarian cancer genetic test?

The blood test for breast or ovarian cancer looks for changes, or mutations, in the BRCA1 and BRCA2 genes. Normally, these genes help control cell growth. Cancer occurs when cells change and grow out of control. Women who inherit these BRCA gene changes have a higher-than-average chance of getting breast or ovarian cancer.

Breast cancer

• Most women who have breast cancer do not have a family history of the disease.
• A family history of breast cancer is not the same as having a BRCA gene change. Most women who have a family history of breast cancer do not have BRCA changes in their family. Between 5% and 10% of women who have breast cancer have an inherited form of the disease. Many of these are related to BRCA1 and BRCA2 gene changes.¹
• Inheriting a BRCA gene change does not mean you will get cancer.
• Not having a BRCA gene change does not mean you will not get breast cancer—it means you have an average chance of getting cancer.
• Women who have a BRCA1 or BRCA2 gene change have a 3 to 7 times higher chance of getting breast cancer compared with other women who do not have these gene changes.¹
• Breast cancer is very rare in men but BRCA2 gene changes have been linked to male breast cancer.

Ovarian cancer

• A woman with a BRCA gene change could have a 16% to 60% chance of ovarian cancer. This means that as many as 600 out of 1,000 women with this change may get ovarian cancer. A woman without BRCA changes has a 17 in 1,000 chance of ovarian cancer.¹
• Inheriting a BRCA gene change does not mean you will get ovarian cancer.
• Not having a BRCA gene change does not mean you will never get ovarian cancer—it means you have an average chance of getting it.

If you have a strong family history of breast or ovarian cancer, this test can be one factor you consider when deciding whether you should take steps to lower your chance of cancer. Those actions may include taking medicine or having your breasts, ovaries, or both, removed. In deciding whether to have the test, you need to weigh your personal and family risks and your feelings, finances, and relationships with others.

Consider having genetic counseling to help you understand the benefits, risks, and possible outcomes of testing. Genetic counselors are trained to explain the test and its results. To find health professionals who provide genetic testing and counseling, call the cancer information service at the National Cancer Institute at 1-800-422-6237 (1-800-4-CANCER). To find a genetic counselor near you, contact the National Society of Genetic Counselors at (312) 321-6834 or visit their Web site at www.nsgc.org.

What do the results mean?

A negative result means you do not have changes in BRCA1 and BRCA2 genes. A positive result means you do have a change on one or both of the genes. Sometimes the test result is uncertain—neither positive nor negative.

It may take several weeks for you to get the results.

Is testing accurate?

No test is 100% accurate. The BRCA test cannot find all possible changes to the genes. It is possible that the test will show you do not have genetic changes when you do. This is called a false-negative test result.

Your test would be most helpful if you first had a close family member who had breast or ovarian cancer genetic tests. If this person tested positive, it means there is a known BRCA change in your family. If the family member's test results are negative, it usually is not helpful to test the rest of the family.

If you have a strong family history of breast or ovarian cancer, a negative BRCA result does not mean that you will not get cancer. There are other causes of breast and ovarian cancer.

BRCA testing sometimes shows genetic changes that may not be linked to cancer. More research is needed to find out if these changes increase cancer risk.

Should I be tested?

You may have several reasons to have the test:

• If you test positive, you would consider steps to lower your chance of cancer. These steps might include:
  • For breast cancer, regular clinical breast exams and mammograms, taking medicine, or having your breast tissue removed.
  • For ovarian cancer, having your ovaries removed.
• You would feel anxious not knowing if you have a higher chance of cancer.
• You have a family history of breast or ovarian cancer. The chance is highest if you have two or more close relatives (mother, sister, or daughter) who have had breast or ovarian cancer, especially at a young age.
• You are of Ashkenazi (Eastern European) Jewish ancestry, with a personal or family history of breast or ovarian cancer. This group has a higher chance of having a BRCA gene change.
• Your insurance covers some or all of the cost of testing.
• If you test positive, you want to alert other family members (such as a sister or daughter) so they may consider having the test.

Why would I not be tested?

You may have several reasons not to have the test:

• You may face difficult emotions. You may be afraid and anxious if you test positive. You may feel guilty if you test negative and someone in your family tests positive.
• You are concerned about how the results might affect your relationships. You have to decide if you would tell a family member—a sister or daughter, for example—who then has to decide if he or she wants to have the test.
• Your insurance does not cover the testing, or covers only some of it. Genetic testing can be very expensive (several hundred to several thousand dollars).
• You are concerned about how the information might affect your employment or your health, life, and disability insurance.
• You would not take preventive steps—such as regular exams and tests, taking medicine, or having your breasts or ovaries removed—no matter what the test results are.