Download When to consider genetic testing

April 2014
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level of cancer care in the
greater Lehigh Valley and
surrounding communities.
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If you are concerned that
the cancer in your family
may be hereditary, speak
to your doctor. You also
can call the St. Luke’s
Family Cancer Risk
Evaluation Program at
610-628-8010 or St. Luke’s
HOPE Line at 484-503HOPE (4673) for more
information about genetic
counseling and testing.
When to consider genetic testing
St. Luke’s Genetic Counselor Andrea Smith discusses when testing should be considered
Genetic testing for cancer-related genes has become an
important part of the cancer diagnosis and treatment process.
However, many people never think about genetic testing until
their doctor tells them that they may want to consider testing
and that they should go see a genetic counselor.
It has long been recognized that certain types of cancer can
“run through families.” However, much more recently, we have
begun to understand how individual genes play a part in the
development of cancer. The BRCA 1 gene was first described in
1990. The discovery of this gene helped to further understand
how a change, or mutation, in a single gene can lead to
significantly elevated risks of certain cancers.
At a basic level all cancer is genetic. Over time, the genes in our cells accumulate damage
due to environmental exposures and normal aging. This damage can affect the way a cell
grows and behaves, potentially leading to the development of a cancer. However, only a
small percentage of cancer is hereditary. In hereditary cancer families, a person may
inherit an already damaged copy of a gene. When this happens, it takes less time for
genetic damage to accumulate and cancer can occur earlier and more often.
Through a simple blood or saliva test, we can now determine if an individual carries a
damaged copy of a gene that would put him or her at an increased risk to develop cancer.
Genetic testing can help determine if medical management options such as increased
screening, risk-reducing medications and preventative surgeries might be beneficial.
When an individual is found to carry a cancer-causing gene mutation, other family
members can be tested to determine if they carry it as well. Any family members who are
found to have the gene mutation can then be offered extra screening and preventative
measures, while family members who do not carry the gene mutation can avoid these
additional procedures.
While the breast and ovarian cancer genes, BRCA 1 and BRCA 2, are the most widely
known cancer genes, there are many different cancer predisposition syndromes that can
lead to a variety of cancers. Cancers such as colorectal cancer, stomach cancer, thyroid
cancer, and uterine cancer can also be hereditary. In hereditary cancer families, we often
see multiple family members diagnosed with the same type of cancer, individuals
diagnosed with cancer at young ages (often under 50), individuals with rare cancers, or
multiple separate cancers in one person.
It is important to keep in mind that these hereditary cancer syndromes are rare and
genetic testing may not be helpful in all families. Also, there are many other factors that
can affect cancer risk, both genetic and non-genetic.