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Every woman is born with the BRCA1 (breast cancer gene 1) and BRCA2
(breast cancer gene 2) genes. When functioning normally, these genes do not pose any risk
to a womans health. However, some women may be born with or experience mutations of
the BRCA genes through their lifetime. Though researchers are still uncertain what causes
changes in these genes to occur, women who have BRCA mutations are at increased risk for
developing breast cancer compared with women who do not have these mutations. For example,
a 30-year-old woman with a BRCA mutation has a 1 in 3 chance of developing breast cancer
during her lifetime (compared with a 1 in 8 chance for women without these genetic
mutations). Over a lifetime, women with BRCA mutations have a 50% to an 85% chance of
developing breast cancer.
In 1996, the American Society of
Clinical Oncology recommended that only women with a strong family history of breast
cancer or those who have developed breast cancer at an early age may be eligible for BRCA
genetic testing and most physicians still adhere to this recommendation today. Candidates
for BRCA testing include those women with:
- Breast cancer in two or more close
relatives, such as a mother and two sisters
- Early onset of breast cancer in family
members, often before age 50
- History of breast cancer in more than
one generation
- Cancer in both breasts in one or more
family members
- Frequent occurrence of ovarian cancer
- One or more BRCA positive relatives
- Eastern and Central European (Ashkenazi)
Jewish ancestry, with a family history of breast and/or ovarian cancer (researchers have
identified two types of BRCA1 mutations and one BRCA2 mutation that are especially
prominent in this group)
Though many women who have already
developed breast cancer do not see the need to be tested for BRCA mutations, benefits of
knowing may include: better response to treatment designed for BRCA-positive women and
helping other family members to take preventive measures against breast cancer.
Genetic
Testing Process |
| Step 1:
counseling session
Step 2: blood is drawn and analyzed
Step 3: test
results are discussed |
The first step involves genetic
counseling. In this session, a counselor will discuss the tests, possible risks (such as
psychological effects, employer concerns, insurance difficulties), and what a positive or
negative result means. During the second session, the blood test and genetic analysis will
be performed. At the third session, the results of the test will be discussed with the
patient. Most genetic testing is anonymous; women do not give out their name and are
randomly assigned a number for identification and future contact.
Women who test positive for BRCA
mutations are at a higher risk for breast cancer. Consequently, relatives of these women
may also be at increased risk for breast cancer BRCA-positive women should practice
monthly breast self-examination, have frequent clinical breast exams (at least once a year), and have a
yearly mammogram so that if breast cancer is detected, it
may be treated at an early stage. BRCA-positive women should
also talk to their physician about beginning screening mammogram at an earlier age, maybe
even as early as 25.
In addition to breast cancer screening,
women who test positive for BRCA mutations should consider lifestyle changes such as
eating healthier, limiting alcohol consumption,
exercising, and maintaining a healthy weight. Women may also consider breast cancer
prevention with the drug tamoxifen or prophylactic mastectomy
(preventive removal of the breasts). However, physicians do not usually recommend
prophylactic mastectomy since testing positive for BRCA mutations does not guarantee that
a woman will develop breast cancer. Click here to
learn more about preventing breast cancer in BRCA positive women.
Genetic testing has been a
controversial topic among medical professionals for several years now. Women with a strong
family history of breast and/or ovarian cancer should weigh the advantages and
disadvantages of genetic testing carefully before reaching a decision. Though most testing
centers require genetic counseling prior to testing, all women considering genetic testing
should discuss their situation with a counselor or physician.
Advantages to testing for BRCA
mutations:
- Women may feel relieved knowing for
certain whether or not they are at a higher risk for breast cancer.
- Women with breast cancer may have better
responses to certain treatments that are specifically designed for BRCA positive patients.
- Women may take preventive measures to help reduce their risk of
breast cancer if they test positive for BRCA mutations (such as making changes in diet,
exercising, or taking tamoxifen).
- Other family members may decide if they
wish to be tested for BRCA mutations based on the results of a womans test. (However, testing
positive for BRCA mutations does not necessarily mean a woman will develop breast cancer. She is
at higher than average risk for the disease, though).
Disadvantages to testing for BRCA
mutations:
- Women may become worried, panicked, or
stressed if they discover they have a higher than average risk for breast cancer.
- Women who test positive for BRCA
mutations are faced with the difficulty of telling family members (some of whom may also
be at increased risk for breast cancer).
- Women who test negative for BRCA
mutations may falsely believe they will never get breast cancer.
- Women who test positive for BRCA
mutations may have to deal with complications with health insurance (if they are not
tested anonymously)
- To date, no studies show
that health insurance providers will reduce coverage or cancel a
policy based on genetic test results. However, women should be made aware of the possibility.
Regardless of the test results, all
women should still take preventive measures to help reduce their risk of breast
cancer. These preventive measures include: practicing monthly breast
self-examination, having regular clinical breast
exams, and having yearly mammograms (at 40 years of age
and older). Though testing from BRCA mutations may help identify women who are at a higher
risk for breast cancer, 80% of women who develop breast cancer have no known risk factors.
Most physicians recommend against BRCA
testing if a woman is not ready to take specific action if she tests positive. Tamoxifen
may be used to help prevent breast cancer without knowledge of specific gene mutations.
Updated: December 17, 2007
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