Who Needs Genetic Testing for Cancer?

If you or someone in your family is diagnosed with cancer, it’s understandable that you’d be concerned as to whether or not this diagnosis puts you or your family members at an increased risk of developing cancer. It’s also understandable that you’d want to encourage your blood relatives to pursue genetic testing as soon as possible. While these thoughts certainly stem from the best of intentions, it’s important to understand that genetic testing isn’t beneficial for everyone. Genetic testing is only helpful in predicting certain types of cancers in a small percentage of people.

Lifestyle Cancer Risks vs. Genetics Cancer Risks

You might find it surprising that only 5% to 10% of cancer cases are related to genetics. Lifestyle is actually a more significant factor than genetics when it comes to cancer risks. Certain types of cancers are more likely to be related to hereditary factors. Those cancers include:

  • breast cancer
  • colorectal cancer
  • endometrial cancer
  • pancreatic cancer
  • ovarian cancer
  • prostate cancer

However, these types of cancer are because the percentage of hereditary cancers is so low, it is often best for most people to focus on things that they can control like lifestyle factors that could increase their cancer risk. Risky lifestyle choices such as smoking, excess drinking, unhealthy eating habits, not exercising, and excess sun exposure are controllable. However, other people who meet certain criteria (listed out below) can undoubtedly benefit from the information that can come from genetic testing. 

When Undergoing Genetic Testing for Cancer Makes Sense

Before deciding if genetic testing would be beneficial, you should do some homework. Contact as many relatives as possible and create a family tree to map out your family’s cancer history. Do the best you can in regards to filling in the cancer histories of your first-degree relatives (parents, siblings, and children) and second-degree relatives (grandparents, aunts, uncles, nieces, and nephews). Genetic testing may be warranted if one or more first- or second-degree relatives have:

  • Been diagnosed with any cancer before the age of 50
  • Three, or more relatives, with cancers linked to certain hereditary factors, including breast cancer, ovarian cancer, pancreatic cancer, or aggressive prostate cancer.
  • The same type of cancer among many relatives on one side of the family
  • Ovarian cancer diagnosed, at any age
  • Known genetic mutations, such as BRCA1 or BRCA2
  • Been diagnosed with more than 20 colon polyps
  • One person has been independently diagnosed with two or more different types of cancer
  • Any rare cancers, such as sarcoma or male breast cancer
  • Cancer in both organs of a paired set of organs, such as both breasts
  • Rare tumors such as medullary thyroid carcinoma, paragangliomas, pheochromocytomas, or desmoid tumor
  • Ashkenazi Jewish ancestry

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

Are You Emotionally Prepared to Handle the Results?

Even if you or your loved ones are appropriate candidates for genetic testing, that does not necessarily mean you should get genetic testing. Genetic testing for hereditary cancer markers can be potentially life-changing, and before you decide to pursue, it’s best to consider and prepare for all possibilities. Additionally, when someone discovers they’re at increased risk of developing cancer, that may mean their close relatives have the same chances. Before undergoing genetic testing, it may be wise to discuss the topic with your close relatives and find out if they want to know the results (since the results could affect them, as well.)

It can be scary to find out you are at an increased risk of developing cancer. With that said, having more insight may allow you to receive medical interventions that will reduce your risk (such as earlier screening or preventive mastectomies to reduce the risk of breast cancer). Furthermore, just because you learn you have an increased risk of cancer does not mean you will 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 visit our Genetic Testing FAQs page.