The breast cancer genetic test is a blood test to find out if there are changes (mutations) in the BRCA1 and BRCA2 genes. This genetic test can help people understand their chances of developing breast and ovarian cancer. However, the BRCA genetic test does not detect cancer itself.
If a woman has a BRCA1 or BRCA2 gene change, it indicates an increased risk of breast and ovarian cancer, men with these gene mutations also have an increased risk of breast cancer, and people with the mutations may have an increased risk of other cancers, regardless of gender. These mutations may be inherited from the mother’s or father’s family.
BRCA1/BRCA2 genetic testing is only indicated for people who have a strong family history of breast or ovarian cancer or who have had these diseases. If these conditions are not present, mutations in the BRCA gene are unlikely. Only about 2 to 3 out of 1000 adult women have a BRCA gene mutation. This means that out of 1000 women, 997 or 998 do not have this change.
It is important to get genetic counseling before and after testing. This may help people understand the benefits, risks, and possible outcomes of genetic testing.
Should I get genetic testing?
The purpose of BRCA genetic testing is to determine if there are mutations in the BRCA gene that may increase the risk of developing breast and ovarian cancer. A BRCA gene mutation is more likely to be present if:
- One or more male family members have had breast cancer;
- Multiple breast cancer patients in the family;
- Multiple breast cancer patients in the family;
- Multiple breast cancer patients in the family
- At least 1 family member has had a BRCA-related cancer.
BRCA gene test results can help people clarify how high their cancer risk is. If the risk is high, a decision may be made to take steps to reduce the risk. Steps that can be taken include:
- getting screened and tested more frequently;
- Get a mastectomy;
- getting an oophorectomy;
- Take medications that may help prevent breast cancer.
If 1 family member has breast or ovarian cancer, consider having the affected family member tested for BRCA first before deciding to get genetic testing yourself. If this family member’s genetic test reveals a BRCA gene mutation, then you and other family members can also be tested for the BRCA gene mutation. However, if this family member’s test is negative, it is unlikely that he or she will have a mutation.
How do I prepare?
The information you get from BRCA genetic testing can make a difference in your life. Therefore, it is very important to have genetic counseling before having this test. A genetic counselor can answer questions about the test, the results, and the counselor’s medical and personal emotional concerns.
People who are tested will be asked to sign a consent form indicating that they understand the risks of the test and agree to complete it.
Consult your doctor if you have any questions about the need for genetic testing, the risks, and how to perform it.
How is it performed?
The health care provider who collects the blood sample will:
- Wrap a rubber tubing tourniquet around the subject’s upper arm to stop the blood flow. This makes the vein under the rubber tubing tourniquet thicker and therefore easier to insert the needle into the vein.
- Clean the area where the needle is to be inserted with alcohol.
- Penetrate the needle into the vein.
- A tube is attached to the needle and blood is drawn.
- When enough blood has been collected, remove the rubber tubing tourniquet from the subject’s arm.
- While removing the needle, place a gauze pad or cotton ball at the site of needle insertion.
- Pressure is applied to the site for several minutes.
When collecting blood from a vein in the arm, a rubber tubing tourniquet is wrapped around the upper arm, and the subject may feel constricted. There may be no sensation when the needle is inserted, or a brief tingling or pinching pain may be felt.
It is normal to feel anxious before the BRCA test and while waiting for the test results.
What are the risks?
There are no risks.
The probability of having a problem with a blood sample collected from a vein is very low and may include:
- There may be a small area of bruising at the site of the needle. Pressure can be applied to the needle site for several minutes to reduce the likelihood of ecchymosis.
- In rare cases, the vein may swell after the blood sample is collected. Hot compresses may be applied several times daily.
- The knowledge that you carry a high-risk cancer gene or that you may pass this risk on to your children may cause anxiety or depression. This information may also affect people’s relationships with their spouses or other family members.
- If a person tests positive for a BRCA gene mutation, they will face difficult decisions about risk reduction options, such as having their breast surgically removed (mastectomy).
- People may be concerned that genetic information may affect their job choices or ability to obtain insurance.
- Only about 5% to 10% of breast and ovarian cancers are associated with mutations in the BRCA1 or BRCA2 genes.
- People may have other mutations in genes that make cancer more likely to occur.
- Women with a mutation in the BRCA1 gene have about a 41% to 90% chance of developing breast cancer at some time in their lives.
- Women with a mutation in the BRCA2 gene have about an 8% to 62% chance of developing ovarian cancer sometime in their lifetime.
- A negative BRCA result is not a guarantee against breast cancer. mutations in the BRCA gene do increase the risk of breast cancer, but there are other genetic mutations that can also cause cancer.
- If you have a family member with breast or ovarian cancer, you should consider having that family member tested for BRCA first before deciding to get this test yourself. If that family member tests negative, it may not make sense to test the rest of the family.
- BRCA testing is not recommended for women who do not have family risk factors for BRCA mutations. If there are no risk factors in the family, BRCA testing is unlikely to provide any useful information about breast cancer risk. Women with an average family risk of the disease rarely have a positive test result. Sometimes, a test may show a positive result in the absence of a mutation, a condition called a false positive.
Bleeding may be a problem for people with bleeding disorders or those taking blood-thinning medications such as aspirin or warfarin. If you have a bleeding or clotting disorder, or are taking blood-thinning medications, you should inform your doctor before taking a blood sample.
The information obtained from BRCA testing may also affect people and their families in many ways.
How do you feel about test results?
The results of a BRCA genetic test can take weeks to come back.
What does normal (negative) mean
Negative means that no BRCA1 or BRCA2 gene mutations were found, but a negative result must be considered in relation to overall family risk. If a person has a strong family history of breast or ovarian cancer, their cancer risk is still higher even with a negative BRCA test result.
What does abnormal (positive) mean
A positive result means there is a mutation in the BRCA1 or BRCA2 gene.
The size of the risk of developing the disease will depend on the type of gene people carry and their personal and family history of cancer.
Men with a BRCA1 mutation also have an increased risk of breast cancer and other possible cancers, such as pancreatic, testicular, or prostate cancer.
Results are unclear (variants of uncertain significance, VUS)
This result may mean that there is a genetic alteration, but it is difficult for doctors to say whether the alteration is significant and whether the alteration affects the risk of developing cancer.
What to look for.
There are some important things to remember when considering getting tested for the BRCA gene.
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Seeking genetic counseling before and after BRCA testing can help people understand the benefits, risks, and possible outcomes of this testing.