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Should You Consider Genetic Counseling and Testing?

by Ellen T. Matloff, MS, CGC, and Karina L. Brierley, MS, CGC

Over the past decade, genetic counseling and testing have become recognized as critical tools in the fight against cancer. The results can guide surgical decision-making, surveillance, and chemoprevention (taking a medication, like tamoxifen, to reduce the future risk of developing cancer), and can be of great use to family members. Although more and more people newly diagnosed with cancer are being referred for genetic counseling and testing, cancer survivors who were diagnosed before the genetic revolution, or who live in areas without active genetics programs, may not have been offered these services.

What is genetic counseling?
Genetic counseling is a communication process that includes a thorough investigation of your personal and family history to determine if the cancers in your family appear to be caused by a single genetic mutation (change in the genetic code) and in which gene it appears (there are many different genes that cause a predisposition to cancer). The genetic counselor will help you determine if you are a good candidate for genetic testing, which test would be most appropriate, and if your insurance will likely cover the cost of testing. He or she will discuss the risks and benefits of testing, the medical options related to the outcome, and how testing could benefit you and your family members. The genetic counselor will also interpret the test results for you and relay this information to you and your medical team.

What does genetic testing involve?
Genetic testing can be performed on DNA extracted from a small blood sample, and can sometimes be performed on a cheek brush or saliva sample. The turnaround time for results is generally two to four weeks.

Who is a candidate for genetic counseling?
The majority of cancers are not caused by a single hereditary mutation. However, several factors increase the chance that cancer is hereditary:

• Early age of cancer onset
  When certain cancers are seen at early ages (for example, breast cancer before age 45 or colon cancer before age 50), it greatly increases the chance that the cancer is hereditary, even when there is no other family history of cancer.
• Multiple family members with the same cancer
  If several people on one side of the same family all have the same type of cancer, it increases the chance that these cancers are hereditary.
• Clusters of cancers caused by the same genetic mutations
  If several members of the same family have different cancers that are known to be caused by a single genetic mutation (for example, diagnoses of breast, ovarian, and pancreatic cancers or colon, uterine, and ovarian cancers), the chance that the cancers in the family are hereditary is increased.
• Multiple primary cancers diagnosed in one person
  If a single person develops more than one primary cancer (as opposed to one cancer that spreads to other parts of the body), it increases the likelihood that the person has an underlying genetic mutation. This is particularly true if those cancers fall within the clusters described above.
• Ethnicity
  Certain genetic diseases are more common in every ethnic background. For example, hereditary breast and ovarian cancer is more common in people of Jewish ancestry.
• Unusual presentation
  There are several uncommon cancers (like male breast cancer) and findings (such as colon polyposis) that are more often hereditary and warrant a referral to a cancer genetic counselor.
• Pathological findings
  Pathology is emerging as a critical clue in genetic risk assessment. Certain types of cancers are more likely to be hereditary (like medullary breast cancer), and others are less likely to be associated with some syndromes.

Why would I want to know this information?
Genetic testing can feel like opening Pandora’s Box for some people. However, the information gained can be empowering. It can help you to prevent a future cancer and arm your relatives with knowledge that can help them avoid developing cancer.

Do I really need to see a genetic counselor? Can’t my doctor just order this test?
Perhaps the greatest risk of genetic testing is that your test result will be ordered or interpreted incorrectly. This has been reported many times in the field, resulting in inappropriate surveillance, surgery, and even death. Because this testing has important implications for you and your entire family, it is critical that you work with someone who has graduate training in this area.

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