Breast Cancer Genetic Testing
In the past few years, two genes have been discovered
that place women at extremely high risk for developing breast and ovarian
cancer and, to a much lesser degree, colon cancer. These genes are the
BRCA1 and BRCA2 genes. (BR=breast, CA=cancer)
The gene discoveries in 1994 and 1996 received much attention in the press
as "the" test for breast cancer. However, in reality, it only
shows that there is an altered (mutated = changed) cell that indicates
the carrier is at very high risk for cancer development. The test is only
appropriate for a small number of women and men and not
the general public. It is estimated that only about 7 - 10%
of breast cancers are caused by these mutated genes.
Women who inherit the BRCA1 gene have a 56 - 80% risk
of having breast cancer by the age of 70 and also have a 40 - 60% chance
of developing ovarian cancer. Men who have the gene have an increased
risk for prostate cancer. There is also an increased risk for both men
and women of developing colon cancer.
People who inherit the BRCA2 gene also have the same
risk for developing breast cancer as in BRCA1 but have a reduced risk
of between 15 - 20% of ovarian cancer. The BRCA2 gene increases the risk
for men to have breast cancer as well as prostate cancer.
These altered genes are inherited from a mother or father.
They can then be passed on to your children (male or female) if you are
a carrier, placing them at higher risk for breast, ovarian/prostate or
colon cancer. Your children are at 50% risk of inheriting the altered
gene if you are a carrier.
People can now have a blood test to determine if they
are a BRCA1 or BRCA2 gene carrier increasing their risk for these cancers.
To determine if you are a candidate for genetic testing, you will need
a risk assessment from a professional medical team trained to evaluate
your family history to see if you meet the strict criteria for testing.
If your history determines you are a candidate, counselors will discuss
with you the advantages, disadvantages and limitations of testing. You
will be given an opportunity to decide if you wish to further pursue testing.
Testing consists simply of having several tablespoons
(30 ccs, approximately 5 - 6 teaspoons) of blood drawn from your arm and
sent to a laboratory for testing.
Benefits of Testing :
- Allows you to know if you carry one of these altered
genes, putting you at very high risk for developing breast, ovarian/prostate
and, to a lesser degree, colon cancer. You would then be given options
for surveillance to ensure that you have the best chance against developing
the disease. It would also allow you to plan your childbearing if you
are a young woman.
- A negative test would relieve your anxiety about
being a carrier and prevent unnecessary, expensive surveillance tests.
You would be placed back at the normal risk for developing breast cancer.
- Allows family members to choose to be tested or placed
in high-risk surveillance programs for early detection. Early detection
allows breast cancer to be found when it is most successfully treated.
- Assists your physicians in planning treatment protocols
to prevent and/or detect other.cancers.
Potential Disadvantages of Positive Test Results:
Who Is A Candidate For Genetic Testing?
- May face discrimination from insurance providers
to keep or obtain health or life insurance
- May have emotional or psychological problems knowing
you are at high risk for cancer
- Family members may react unpredictably to positive
test results (a positive test places you and possibly them at higher
risk for cancer because same blood line)
- Possibility that positive carrier could be denied
child custody or adoption privileges
for being tested for the BRCA1 or BRCA2 gene is based on the degree of
risk your family or personal history presents.
Testing is now performed for:
*Definition of First- and Second-Degree Relatives
- Person with breast and/or ovarian cancer who has
two or more first* or second-degree* blood relatives (on one side of
family, maternal or paternal) with either breast or ovarian cancer.
- Person with personal diagnosis of breast and/or ovarian
cancer who has one first or second-degree* blood relative younger than
45 (some authorities say 50 years of age or pre-menopausal) with breast
cancer and/or ovarian cancer at any age.
- Personal history of breast/ovarian cancer developed
before age 45 (some authorities say 50 years of age or pre-menopausal)
- Personal history of breast/ovarian cancer that is
bilateral (both sides) or has multiple primary sites of cancer
- Males who develop breast cancer
- Blood relative (first- or second-degree relative*)
of BRCA1 or BRCA2 documented gene carrier
- First-Degree: mother, father, sister, brother,
- Second-Degree: aunt, uncle, grandmother, grandfather,
granddaughter, grandson, niece, nephew, half-brother, half-sister
Genetic Testing Exclusions:
- Person under 18 years of age
- Cognitively impaired person, unable to give informed
- Psychologically impaired according to professional
Decision to Test or Not Test
The decision to have genetic testing should be made
in partnership between you and a professional treatment team who:
- evaluates your risks
- determines whether you meet criteria for testing
- offers you professional psychological counseling
before and after the test results
- answers all of your questions about the process
- provides written information on the test and lab
- obtains informed consent for testing
- protects your confidentiality
- develops a surveillance/treatment plan after testing
For more information, please call The Connie Dwyer Breast
Center at (973) 877-5189.
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