Should You Have Genetic Testing for Breast Cancer?

Every year, thousands of women are diagnosed with breast cancer. About 5 percent to 10 percent of those women have a type of breast cancer that is inherited. This type of cancer is the result of changes (mutations) in certain genes. The ones most commonly involved are the BRCA (BReast CAncer) genes.

Normally, the BRCA1 and BRCA2 genes are tumor suppressors. They help prevent cancer by controlling cell growth. But if either of these genes has mutations, it may no longer work properly. Cells may grow abnormally and form tumors.

The risk of getting breast cancer is much higher than normal for women with BRCA mutations. BRCA mutations also increase your risk for ovarian cancer.

• An average woman in the United States has about a 12 percent chance of getting breast cancer if she lives to the age of 90. Her risk of getting ovarian cancer is about 1.8 percent.
• A woman with BRCA mutations may have up to an 85 percent chance of getting breast cancer by age 70 and between a 25 to 55 percent chance of getting ovarian cancer in her lifetime.

The only way to find out if you have gene mutations is to have genetic testing. But testing is not for everyone.

Who should consider genetic testing?
Many expert groups agree that genetic testing may be a good idea for certain women who are at high risk. BRCA gene changes are inherited, so think about your family background and medical history.

BRCA gene changes are much more common in women with an Eastern European (Ashkenazi) Jewish background. You may want to consider genetic testing if you are an Ashkenazi Jewish woman and:

• A first-degree relative (parent, sibling or child) had breast or ovarian cancer, or
• Two second-degree relatives (aunt, niece or grandmother) on the same side of the family had breast or ovarian cancer

If you aren't Jewish, you may be at high risk for BRCA gene changes if your family medical history includes any one of these:

• Two first-degree relatives with breast cancer and one was diagnosed at age 50 or younger
• Three or more first- or second-degree relatives with breast cancer at any age
• Both breast and ovarian cancer in your family (first- or second-degree relatives)
• A first-degree relative with cancer in both breasts
• Two or more relatives with ovarian cancer (first-or second-degree relatives)
• A relative who had both breast and ovarian cancer (first- or second-degree relative)
• A male relative with breast cancer

Should I have genetic testing?
Genetic testing is a complex issue, so there's no one right or wrong answer to this question. If you could be at high risk for gene changes, talk to a genetic counselor. A genetic counselor can help you understand more about your risk for cancer and weigh the pros and cons of testing.

It may help to think about why you would want this information and what you would do with it.

Reasons you might want to be tested

• If you know you are at high risk, you might explore options to reduce your risk. These include:
• Getting regular breast exams
• Having screening imaging studies, such as mammograms and MRIs
• Having your breasts or ovaries removed
• Taking medicine
• You want to know as much about your risks for cancer as you can.
• If you test positive, you can let other family members know that they should be tested.
• Knowing about a gene mutation would help doctors give you the best treatment if you do get cancer.

Reasons you might not want to be tested

• A positive test result won't change what you are doing. This might be the case if you already get regular breast exams and imaging tests and you would not consider taking medicine or having surgery.
• A normal test result does not guarantee that you are at average risk for cancer. You could still be at high risk from other gene changes that experts have not yet identified.
• Finding out you have an increased risk of cancer may be too distressing. You may feel that you'd rather not know.
• A positive test result might someday affect your ability to get health or life insurance or get a job.

Facts to keep in mind

• Most women who get breast cancer do not have BRCA changes. As many as 95 out of 100 women who get breast cancer don't have them.
• Having BRCA changes does not mean you will get cancer. Up to 15 percent of women with these changes don't get cancer.
• Doctors don't know how to prevent breast cancer; they can only reduce the risk.

Related Articles Calculating Cancer Risk Who Gets Breast Cancer? Should You Have a Mastectomy to Prevent Breast Cancer?

External Sources American Cancer Society. Genetic testing and counseling. Accessed October 11, 2007. BreastCancer.org. Genetics and breast cancer risk. Accessed October 11, 2007. National Cancer Institute. Genetic testing for BRCA1 and BRCA2: It's your choice. Accessed October 11, 2007. U.S. Preventive Services Task Force. Genetic risk assessment and BRCA mutation testing for breast and ovarian cancer susceptibility: Recommendation statement. Annals of Internal Medicine. 2005;143(5):355-361. Accessed October 11, 2007.

Search