Breast Cancer (BRCA) Gene Test

Test Overview

A breast cancer (BRCA) gene test is a blood test to check for specific changes (mutations) in genes that help control normal cell growth. Finding changes in these genes, called BRCA1 and BRCA2, can help determine your chance of developing breast cancer and ovarian cancer. A BRCA gene test does not test for cancer itself. This test is only done for people with a strong family history of breast cancer or ovarian cancer, and sometimes for those who already have one of these diseases. Genetic counseling before and after a BRCA test is very important to help you understand the benefits, risks, and possible outcomes of the test.

A woman's risk of breast or ovarian cancer is higher if she has BRCA1 or BRCA2 gene changes. Breast cancer is extremely rare in men but BRCA2 gene changes have been linked to male breast cancer and possibly prostate cancer. The risk of some other cancers, including pancreatic and colon cancer, may also be higher.¹ The gene changes can be inherited from either your mother's or father's side of the family.

Certain people have a higher chance of inheriting BRCA1 or BRCA2 gene changes.

• Jewish women are more likely to be BRCA gene carriers. Some experts recommend gene tests for women who are Ashkenazi Jews (Jews whose ancestors came from Eastern Europe) if they have one or both of the following:²
  • Any first-degree relative with breast or ovarian cancer. First-degree relatives are parents, sisters and brothers, and children.
  • Two second-degree relatives on the same side of the family with breast or ovarian cancer. Second-degree relatives are aunts and uncles, nieces and nephews, and grandparents.
• If you are not Jewish, some experts recommend a gene test if you have one or more of the following:²
  • Two first-degree relatives with breast cancer, one of whom was diagnosed before age 50
  • Three or more first- or second-degree relatives with breast cancer, diagnosed at any age
  • Both breast and ovarian cancer in the family
  • A first-degree relative with cancer in both breasts
  • Two or more relatives with ovarian cancer
  • One relative with both breast and ovarian cancer
  • A male relative with breast cancer

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Why It Is Done

A BRCA gene test is done to check your chance of developing breast cancer if your family history or personal history indicates a high chance for this cancer.

A BRCA gene test does not test for cancer itself. It is used to help women with a strong family history of breast or ovarian cancer find out if their chance is high enough to think about prevention measures-such as taking medicine (tamoxifen), having a preventive mastectomy, or having their ovaries removed (oophorectomy)-before cancer develops.

Men with a family history of BRCA changes also may want to be tested to find their chance of breast or prostate cancer.

For a person who has breast or ovarian cancer, results from a BRCA gene test can help other family members know their chances of these and perhaps other cancers. If the person with breast or ovarian cancer has normal BRCA gene test results, family members probably would not benefit from the BRCA genetic test.

How To Prepare

Genetic counseling is strongly recommended before and after a BRCA test to help you understand the benefits, risks, and possible outcomes of the test. A BRCA test gives you the chance to make informed medical and lifestyle decisions. But information about having gene changes could affect your employment or your health, life, and disability insurance. Genetic counselors are trained to talk with you about the test and its results, including the medical information and your emotional concerns.

This test can cause a great deal of worry, both before and after the test. Talk with a genetic counselor before the test to help you prepare for and cope with this worry. Think about what you may do if your test is positive. For example, would you consider any prevention measures, such as the following:

• For breast cancer: A yearly mammogram, a clinical breast exam at regular times, preventive mastectomy (removal of both breasts), taking a medicine (tamoxifen), or having your children before age 30
• For ovarian cancer: Using birth control pills or having your ovaries removed (oophorectomy)

You will be asked to sign a consent form before the test. Talk to your health professional about any concerns you have regarding the need for the test, its risks, or how it will be done. To help you understand the importance of this test, fill out the medical test information form (What is a PDF document?) .

No other special preparation is needed before you have this test.

Should I have a gene test for breast and ovarian cancer?

How It Is Done

The health professional drawing blood will:

• Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
• Clean the needle site with alcohol.
• Put the needle into the vein. More than one needle stick may be needed.
• Attach a tube to the needle to fill it with blood.
• Remove the band from your arm when enough blood is collected.
• Apply a gauze pad or cotton ball over the needle site as the needle is removed.
• Apply pressure to the site and then a bandage.

How It Feels

The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.

It is common to worry before a BRCA test and while waiting for its results.

Risks

There is very little chance of a problem from having blood sample taken from a vein.

• You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
• In rare cases, the vein may become swollen after the blood sample is taken. To treat this, you can use a warm compress several times a day.
• Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.

Some women may be worried about the test results and how it will affect their lives, their work, and their health, life, or disability insurance.

Results

A breast cancer (BRCA) gene test is a blood test to check your chance of developing breast cancer and ovarian cancer. Test results may take several weeks.

Normal (called negative)

No changes were found in the BRCA1 or BRCA2 genes.

A negative result and your overall family risk must be considered together.

• If a family member has a known BRCA change, other family members may want to be tested.
• If other family member test results are also negative (even though you have a family member with a BRCA change), it is unlikely that you have inherited an increased risk of developing cancer in this way. In this case, you have the same chance of cancer as that of the general public, based on your age and personal and family history.

Only about 5% to 10% of breast and ovarian cancers are linked to the BRCA1 or BRCA2 gene change. If you have a strong family history of breast or ovarian cancer, you may still have a higher chance of developing breast cancer even if you have a negative BRCA result. Other gene changes are possible that make cancer more likely.

Abnormal (called positive)

BRCA1 or BRCA2 gene changes are present.

Women who have BRCA1 or BRCA2 gene changes have between a 36% and 85% chance of developing breast cancer and between a 16% and 60% chance of developing ovarian cancer during their lifetimes.¹ These numbers show a wide range of chance and depend on your other personal and family history.

Men with BRCA1 or BRCA2 gene changes have a higher risk of breast and prostate cancer.¹

The risk of other cancers, including cancer of the pancreas and colon, may also be higher with BRCA1 or BRCA2 gene changes.¹

Uncertain (called variant of uncertain significance or VUS)

This result may mean that a gene change is present but it is difficult for your doctor to know if the change is important and if it changes your chances of developing cancer.

What Affects the Test

Your doctor will talk with you about anything that may stop you from having the test or that may change the test results.

What To Think About

There are several important things to think about when you are making the decision to have a BRCA gene test.

• Genetic counseling before and after a BRCA test will help you understand the benefits, risks, and possible outcomes of testing. A BRCA test gives you the chance to make informed medical and lifestyle decisions. For more information, see the topic Breast Cancer Genetic Test. However, information about having gene changes could affect your employment or your health, life, and disability insurance. To find doctors who do gene tests and counseling, call the cancer information service at the National Cancer Institute at 1-800-4-CANCER (1-800-422-6237). 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.
• About 5% to 10% of all breast and ovarian cancers are linked to the BRCA1 or BRCA2 gene change.³ If you test positive for one of these changes, your lifetime chance of breast cancer is 36% to 85% and your chance for ovarian cancer is 16% to 60%.¹ These numbers show a wide range of chance and depend on other personal and family history.
• If you have a strong family history of breast cancer, a negative BRCA result does not mean that you will not develop breast cancer. BRCA1 and BRCA2 gene changes do cause a higher chance of breast cancer, but other gene changes are possible and may cause cancer.
• If you have a family member with breast cancer, think about asking the family member to be tested for a gene change before you have a test. If your family member's BRCA tests results are negative, it usually is not helpful to test the rest of the family.
• Genetic tests can be very expensive (costing hundreds to thousands of dollars) and may not be covered by your health insurance.
• The United States Preventive Services Task Force (USPSTF) does not recommend regular BRCA testing for women who do not have family risk factors.²
• For women from families that do not have risk factors for BRCA changes, a genetic test is not likely to give any useful information about their chance of developing breast cancer. Women from low-risk families rarely have a positive test. A BRCA gene test is not recommended for a person without risk factors, because the test can give a false-positive test result.

Should I have a gene test for breast and ovarian cancer?

What should I do if I'm at high risk for breast cancer?

References

Citations

1. National Cancer Institute (2002). Genetic testing for BRCA1 and BRCA2: It's your choice. Available online: http://www.cancer.gov/cancertopics/factsheet/Risk/BRCA.

2. U.S. Preventive Services Task Force (2005). Genetic risk assessment and BRCA mutation testing for breast and ovarian cancer susceptibility: Recommendation statement. Annals of Internal Medicine, 143(5): 355-361.

3. National Cancer Institute (2007). Genetics of Breast and Ovarian Cancer (PDQ)-Health Professional Version. Available online: http://www.cancer.gov/cancertopics/pdq/genetics/breast-and-ovarian/healthprofessional.

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