Who Should Get Genetic Testing?

As a cancer survivor, it’s only natural to wonder if your diagnosis puts your family members at an increased risk of developing cancer. You may assume that the best way to address this question is to encourage your blood relatives to pursue genetic testing as soon as possible. “After all,” you may reason, “Knowledge is power!” That may be true, but you may be surprised to learn that genetic testing for cancer is only helpful in predicting cancer in a small percentage of individuals.

Lifestyle Trumps Genetics When It Comes to Cancer Risk

Cancer experts say that only 5% to 10% of cancer cases are related to genetics. And certain types of cancers, like breast cancer, ovarian cancer, prostate cancer, pancreatic cancer, colorectal cancer, and endometrial cancer, are more likely to be hereditary. When you think about it, that’s actually very good news. You cannot do anything about the genes you were born with. You absolutely can control lifestyle factors (smoking, excess drinking, unhealthy eating habits, not exercising, excess sun exposure) that increase your cancer risks. For certain individuals, though, genetic testing can yield important information about cancer risk.

When Does It Make Sense to Undergo Genetic Testing for Cancer?

Before deciding if genetic testing would be beneficial, you and/or your loved ones should put pen to paper, contact as many relatives as possible, and create a family cancer history map. Focus on filling in the cancer histories of as many first-degree (parents, siblings, and children) and second-degree (grandparents, aunts, uncles, nieces, and nephews) relatives as possible. Genetic testing for cancer may be warranted if one or more first- or second-degree relatives has been diagnosed with:

  • Cancer before the age of 50
  • The same type of cancer
  • Two or more different types of cancer that have occurred independently in the same person
  • Ovarian cancer at any age
  • A rare cancer such as sarcoma or male breast cancer
  • Cancer in both organs of a set of paired organs, such as both kidneys or both breasts
  • A genetic mutation such as BRACA1 or BRACA2
  • More than 20 colon polyps

Additional genetic risk factors include certain ethnic predispositions, specifically Ashkenazi Jewish ancestry and/or having three or more relatives who have developed breast cancer, ovarian cancer, pancreatic cancer, and/or an aggressive prostate cancer.

If family history raises red flags, your or your relative’s doctor will probably recommend meeting with a genetic counselor for genetic counseling. A genetic counselor will be able to further pinpoint the odds of having a genetic mutation that raises the risk of certain types of cancers. Based on the genetic counselor’s findings, he or she will share whether or not they recommend testing.

Are You Prepared Emotionally?

Even if you or your loved ones are deemed excellent candidates for genetic testing, that does not necessarily mean you should immediately set up an appointment to get it. Genetic testing can be potentially life-changing, and before you decide to pursue testing, it’s smart to consider and prepare for the “what-ifs.” Additionally, when someone discovers they’re at increased risk of developing cancer, that may mean their close relatives have the same risk. Before someone undergoes genetic testing, it may be wise to discuss that with their close relatives and find out if they want to know the results (since the results could affect them, too.)

Discovering you are at increased risk of developing cancer can be scary. However, that knowledge may allow you to receive medical interventions that will reduce your risk (such as preventive mastectomies to reduce the risk of breast cancer). And, just because you learn you have an increased risk of cancer, that does not mean you will definitely develop cancer. If you would like to learn more about whether or not genetic testing is right for your loved ones, we encourage you to consider Compass Oncology’s Genetic Risk Evaluation & Testing (GREAT) program. Program participants gain expert guidance from physicians and nurses who specialize in cancer genetics and genetic counseling.