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
It is important to remember that:
- 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 these 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 changes.1
- Breast cancer is very rare in men; however, BRCA2
gene changes have been linked to male breast cancer.
Ovarian cancer
A woman with a BRCA gene change could have as high as a 60%
chance of ovarian cancer. This means that 600 out of every 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 However, it is
important to know that inheriting a BRCA gene change does not mean you will get
ovarian cancer. Also, 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 (610) 872-7608 or http://www.nsgc.org.