| The
Role Of Genetics |
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| A minority of breast cancers
have a genetic basis. When appropriate, genetic counseling
and/or genetic testing may be recommended by the breast surgeon
and/or oncologist. On this web page we are providing a very
brief overview of the genetics involved with breast cancer,
and information on how to learn more. The role of genetics
in the diagnosis and treatment of breast cancer can be confusing,
so we recommend all our patients speak with their breast surgeon,
oncologist, or a genetic counselor if there are any questions.
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| What is a "BRCA"
gene? |
Scientists have identified
two genes linked to breast cancer, known as the BRCA1 and
BRCA2 genes. These genes are believed to play a role in suppressing
tumors and thereby reducing the cancer risk. Everyone has
these genes (male and female). However, some people have mutations
in the BRCA1 or BRCA2 genes - essentially their BRCA genes
do not function properly and these patients are at increased
risk of certain types of cancer such as breast, ovarian, or
prostate cancer. Even if someone has abnormal BRCA genes,
it does not necessarily mean that person will get cancer but
it may mean an increased risk of cancer.
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| What
percentage of breast cancer is believed to be genetic? |
It
is currently believed that approximately 75-78% of all breast
cancer cases are sporadic mutations - meaning they are not
related to a patient's genetics. Approximately 7-10% of all
breast cancer cases are believed to be related to abnormal
BRCA genes. The remaining 15% are considered "familial".
This means there is a family history of breast cancer (or
ovarian cancer) but no abnormal BRCA genes. There may be other
genes involved in these cases which have simply not yet been
identified |
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| What
is genetic testing? |
| Genetic testing typically
involves a patient first being seen by a genetic counselor.
This individual takes a comprehensive medical and family history
on the patient. The patient is then advised regarding the details
of genetics in breast cancer and a recommendation made regarding
genetic testing. The testing itself involves sending a blood
sample to a highly specialized laboratory (Myriad Genetics Laboratories).
The genes are analyzed and results returned to the center conducting
the genetics testing. Patients may then have a second consultation
with the genetics counselor to discuss the results and what
those results may mean for the patient. |
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| What
factors are considered when determining whether a patient should
have genetic testing? |
-
A patient's personal cancer history,
particularly breast or ovarian cancer
-
Bilateral breast cancer (patients with
bilateral breast cancer are more likely to have (abnormal
BRCA genes than those with unilateral breast cancer)
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A family history of breast or ovarian
cancer
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A male with breast cancer in the family
(the BRCA genes are carried by both men and women)
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Breast cancer before the age of 50
-
Ashkenazi/Eastern European Jewish Descent
(there is a higher incidence of abnormal BRCA genes in
this population than in the general populaton)
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| How
does genetic testing affect the breast reconstruction decision? |
A
patient who is found to have an abnormal BRCA gene may be
advised to consider a prophylactic mastectomy on the non-cancerous
breast, or may be advised on a different post-mastectomy treatment
course by the oncologist. This may have an impact on the type
of reconstruction chosen. As an example, consider a hypothetical
patient named Jane who has breast cancer in her left breast
and undergoes a unilateral (one sided) mastectomy with reconstruction
using a DIEP flap (abdominal tissue). Then later Jane undergoes
genetic testing and learns she has an abnormal BRCA gene and
is advised to undergo a prophylactic mastectomy on the right
side. Because she has already used her abdominal tissues for
the first reconstruction, she will now have to choose a different
type of reconstruction for the right breast. If genetic counseling
was done prior to the original mastectomy and reconstruction
she might have chosen to have both mastectomies done originally
and been able to have a DIEP done on both breasts at that
time.
Another way in which genetic testing may affect reconstruction
is with regard to recommendations about post-mastectomy treatment
such as radiation. If it is known a patient will be having
radiation, this may factor into the decision as to the best
type of reconstruction for any given patient.
Other than these two factors, however, reconstruction is
not affected by BRCA gene anomalies.
It is important to note that genetic testing is not necessary
for all patients. Each patient should speak with her breast
surgeon and/or oncologist about this.
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| Does
genetic testing affect eligibility for insurance? |
Patients
are often concerned that abnormal genetic test results may
cause them to lose their insurance or be unable to get new
insurance in the future. However, HIPAA (the federal legislation
that affects many facets of health information) prohibits
the use of genetic test results to determine eligibility or
rates for insurance. In addition, Texas Bill 75RHB prohibits
discrimination in employment or health insurance in group
plans of 50 or more. More information about these legislations
and insurability can be learned from your genetic counselor.
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| Where
can a patient learn more about genetic testing? |
There
are a variety of centers in the DFW metroplex, and throughout
the country, providing genetic counseling and genetic testing.
Check with your physicians for recommendations of a center
near you. The information provided on this page is from a
presentation given to our office by Becky Althaus, RN, PhD,
a genetic counselor with the Baylor W.H. & Peggy Smith
Baylor Sammons Breast Center. Information can be obtained
from that center at 214-820-9600. In addition, Myriad Genetics
Laboratories has educational material which can be found at
their website at www.myriadtests.com. |
