Hereditary Cancer Genetic Testing
Genetics plays an increasing role in cancer care. Your genes influence your height, your eye color and your risk for cancer. Approximately 5-10% of all cancers are caused by hereditary cancer condition due to a gene mutation that a person has had since conception. Individuals with a hereditary cancer condition have increased risks of cancer over their lifetime that can affect multiple body parts. Additionally, these risks may also be present in other family members. Finally, medications and treatments for cancer have been developed to work better for individuals with certain hereditary cancer conditions. For these reasons, hereditary cancer genetic testing can provide valuable information for you and your family.
When is genetic testing recommended?
Genetic testing is recommended when a person or family has certain features that are suspicious for a hereditary cancer condition. First, certain types of cancer have a higher chance of being caused by a gene mutation. For example, approximately 20% of all individuals with pancreatic cancer have a hereditary cancer condition. All individuals with these cancers are recommended to undergo genetic counseling/testing. Another suspicious feature is developing cancer at an earlier than expected age. Most cancers occur as an individual ages so cancers in a younger person, such as breast or colon cancer prior to age 50, warrants investigation. Finally, individuals from families with a strong family history of cancer (meaning three or more related individuals) may qualify for cancer genetic testing. These cancers may all be the same cancer or related cancers. For example, breast, ovarian and prostate cancer are linked genetically. A person with a family history of three relatives on the same side with these cancers may be offered genetic testing.
At WakeMed Cancer Care, our team assesses our patients for these “red flags” and refers appropriate patients to our genetic counseling team for a genetic counseling appointment. You can help this process by collecting and sharing your family history of cancer with your provider. Knowing who in your family has had cancer, what type and at what age allows for a better assessment of whether genetic testing is recommended.
What happens in a genetic counseling appointment?
A genetic counselor is a medical professional with advanced training in genetics and counseling who works with families to investigate whether a hereditary condition is present. Because of the complexity of the test results and the emotions involved, genetic counselors guide patients through the genetic testing process, providing explanation and support at each step.
A genetic counseling appointment takes 30 minutes to 1 hour and can be done either in person at one of two locations or via video visit. During the appointment, the genetic counselor will gather a detailed family cancer history. Once all information is collected, the genetic counselor will discuss whether genetic testing is recommended as well as the benefits, limitations and costs of genetic testing. If a patient chooses to proceed, a blood or saliva sample is collected and sent to a lab for analysis. Results are typically available in 2-3 weeks and the genetic counselor calls the patient to discuss.
What happens if a condition is found?
If a gene mutation is identified, then an individual will have a detailed discussion regarding these results with the genetic counselor. This will include reviewing what types of cancer are associated with the gene, how large are the risks for those cancers and what are the medical management recommendations. For example, Lynch syndrome is a hereditary cancer condition associated with increased risks for colon, stomach, uterine and ovarian cancer. Individuals with this condition are recommended to have frequent screening of their colon and stomach. Women are recommended to be followed closely by a gynecologist and consider a total hysterectomy once childbearing is completed.
What happens if the results are negative?
Even if test results are negative, the genetic counselor may have cancer screening recommendations for you and family members based on the family history of cancer. Approximately 20% of cancers fall into the "familial cluster" category, meaning that cancer occurs within the family in a higher percentage than expected by pure chance. The increased occurrence of cancer in these families is probably due to combination of environmental/lifestyle factors and unidentified genetic factors. Depending on your specific family history of cancer, you may be recommended to have increased cancer screening.
Cancer genetics is a rapidly changing field, with new discoveries happening all the time. As new genes are discovered, you may be offered updated cancer genetic testing.
If you have additional questions about cancer genetic counseling/testing, please speak to your provider or call 919-350-CURE (2873) to schedule an appointment with our genetic counseling team.