Published:
August 31, 2020
If you have a relative who was diagnosed with cancer at a young age, or have several family members with cancer, you may be concerned about your own risk of developing cancer. You may be considering genetic counseling and testing to gain knowledge that could help you make important choices about your health.
As a licensed, certified genetic counselor for the Cancer Risk Evaluation Program (CREP) at the Ann B. Barshinger Cancer Institute, I hear these concerns from patients every day. Below are some questions we discuss as we work through the decision-making process that may help you and your family approach this difficult topic.
Are Most Cancers Genetic?
Only about 10 percent of cancers are hereditary—caused by genetic mutations passed from a parent to child. Most cancers—approximately 90 percent—are actually sporadic, meaning they are caused by changes in genes that take place by chance or as a result of environmental or lifestyle factors.
When Is Genetic Testing Recommended?
Patients receiving treatment for cancer may be referred for genetic counseling by their surgeon or oncologist. Others are referred by a primary care doctor, who may ask about the history of cancer in the family. Patients may also self-refer if their family and/or personal history includes:
- Two or more close relatives on the same side of the family with cancer
- Cancer diagnosed at an early age (younger than age 50)
- The same person has multiple primary tumors
- Bilateral cancer (cancer occurring in both of a pair of organs such as breasts, ovaries, kidneys)
- A pattern of cancers in a family suspicious of a hereditary cancer syndrome
- A very rare cancer (adrenocortical cancer, sarcoma, etc.)
- Triple negative breast cancer under the age of 60, meaning the three most common types of receptors that fuel most breast cancer growth–estrogen, progesterone, and the HER-2/neu gene– are not present in the tumor
Many other specific criteria may suggest genetic counseling is warranted to help determine if a person would benefit from genetic testing.
What Is Involved With Genetic Counseling and Testing?
To begin the genetic counseling process, patients complete paperwork regarding the family and personal history of cancer. When this paperwork is completed and returned, patients are contacted to set up an appointment with a genetic counselor.
At this appointment, patients review their information with a genetic counselor and learn about the risks, benefits and limitations of genetic testing. Genetic counselors help patients to understand if this type of testing would benefit the patients and/or the patient’s family. Genetic testing is done on a blood sample or a saliva sample. The sample is sent to a commercial genetic testing laboratory. It takes about three weeks to get test results back. Interpretation of these results can be difficult, as results are not always a straight forward positive or negative. Counselors will help you understand what your results mean and how your results impact both you and your family.
What Are The Benefits of Genetic Testing?
Meeting with a genetic counselor and undergoing a cancer risk evaluation helps both patients and their families to understand their inherited risk for cancer, and steps they can take to reduce that risk. Genetic counselors follow the current evidence-based guidelines, and collaborate with other members of the cancer team to provide recommendations for follow-up care.
For instance, individuals with hereditary genetic mutations linked with breast cancer may also have a higher risk for ovarian cancer or melanoma. Men in the family could be at a significantly increased risk for prostate cancer or male breast cancer.
Cancer risk evaluation provides options, enabling people to take proactive steps such as starting screenings at an earlier age or increasing the frequency of testing, so problems can be caught early. Genetic test results can also help doctors to choose the most effective treatment for cancer.
Does a Positive Test Mean a Person Will Get Cancer?
If a genetic mutation is identified by this testing, it doesn’t mean an individual will definitely develop cancer in their lifetime. The presence of a genetic mutation means that an individual has a higher risk of developing certain types of cancer, in comparison to the general population. That increased risk of cancer often warrants additional screening and active surveillance, above and beyond what is recommended for the general population.
Learning that you were born with a genetic mutation is never easy. However, the knowledge, along with guidance from a genetic counselor, empowers patients and families to be proactive in reducing their cancer risk and staying healthy.