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 the disease. You may even be considering genetic counseling or testing to gain knowledge that could help you make important choices about your health care.
As a licensed and certified genetic counselor for the Cancer Risk Evaluation Program (CREP) at the Ann B. Barshinger Cancer Institute, I listen to these concerns from patients every day. Below are some questions we discuss to work through the decision-making process, that may help you and your family approach this often difficult topic.
Are most cancers genetic?
Most cancers—90 percent in fact–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 that increase your risk of cancer. Only about 10 percent of cancers are hereditary—caused by genetic mutations passed from a parent to child. Examples include the BRCA 1 and 2 gene- related breast and ovarian cancers and Lynch syndrome-related colon and uterine cancers.
When is genetic testing recommended?
Patients under treatment for cancer may be referred for genetic counseling through their surgeon or oncologist. Others are referred by a primary care doctor who identifies a risk. People 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 grouping of cancers in a family suspicious of a cancer syndrome
- A very rare cancer
- 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 cancer tumor
Many other specific criteria may suggest genetic counseling is warranted to help determine if a person needs genetic testing.
What is involved with genetic counseling and testing?
To begin the genetic counseling process, you complete paperwork that notes your family and personal health history, along with lifestyle risk factors like smoking or being overweight. Once this is returned to the CREP program, you are contacted to make an appointment.
Patients review their information with a genetic counselor and learn the differences between hereditary and sporadic cancers and what genetic testing entails. For those eligible, genetic testing involves blood or saliva tests performed by a commercial laboratory. The tests are painless and very easy. Interpretation is more difficult as results are not always a straight forward positive or negative. Counselors will help you understand the results and so you can make appropriate medical decisions.
What are the benefits of genetic testing?
Meeting with a genetic counselor and undergoing a cancer risk evaluation helps patients and their families better understand their inherited risk for cancer, and steps they can take to lessen that risk. Genetic counselors follow the latest 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 risk for prostate cancer or even 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 are caught early. The information can also help patients make better informed treatment decisions.
Does a positive test mean a person will get cancer?
A positive test for a mutation doesn’t mean a firm cancer diagnosis lies in your future. An environmental influence is needed to start the cancer process. The mutation just means one of the two copies of each gene is unable to provide protection, predisposing the person to develop cancer. It is not until the environment damages the other copy of the gene that cancer may start.
While receiving positive results is never easy, knowledge, along with guidance from a genetic counselor, empowers patients and families to be proactive in reducing their cancer risk.