Being Well

Is Genetic Testing for Cancer Right for You?

Talk to your doctor if you're interested in genetic testing for cancer. It can be performed from a blood sample drawn in your doctor's office.

Whether it’s diabetes or mental illness, you’ve probably heard that something “runs” in your family. Sometimes it’s talking about an admirable physical trait, like dimples or a beautiful smile, but other times it refers to something more dangerous, such as cancer. With genetic testing for cancer, it’s often possible to determine whether you’re at an increased risk of the same cancer that your brother beat 10 years ago or that took your aunt’s life. Find out if this the option for you.

What Is Genetic Testing?

Genetic testing examines your DNA for specific inherited abnormalities, called mutations. Although not all mutations are harmful, genetic tests for cancer look only for those mutations known to increase your cancer risk. Genetic testing for cancer depends on the type of cancer you’re concerned about.

There are more than 50 types of hereditary cancer syndromes most of which are caused by a few specific mutations. These syndromes increase the risk of certain types of cancer. BRCA1 and BRCA2 are probably the most well-known cancer mutations. The National Cancer Institute states these mutations increase the risk not only of breast cancer but also ovarian, prostate, and pancreatic cancers. Other syndromes increase the risk of numerous cancers, including colorectal, stomach, small intestine, liver, brain, endometrial, and ovarian cancers.

Should You Get Tested?

Genetic testing is only recommended when the following conditions are met:

  • There’s a strong family history of cancer.
  • There’s a test available for that specific cancer.
  • Results of the testing can help guide future medical care.

Just because your second cousin died of lung cancer doesn’t necessarily suggest you have an increased risk of that disease. However, cancer in multiple close relatives (parents, siblings, grandparents, aunts and uncles) may indicate a family history.

If you have two or more close relatives with breast cancer, for instance, you may decide to be tested since the BRCA1 and BRCA2 mutations can be tested. If testing shows you have an increased risk of breast cancer, there are steps you might take to reduce your risk, such as having more frequent mammograms, adopting a healthier lifestyle, or even undergoing prophylactic mastectomy which is the surgical removal of the breast(s) before cancer can strike.

How Is Genetic Testing Done?

The DNA for a genetic test is typically collected from a blood sample but can also be done using saliva, cells from the inside the cheek, or even skin cells. This sample is sent to a laboratory and the results generally take several weeks to come back.

Genetic test results can be positive, negative, or inconclusive. A positive test result indicates that an increased risk of cancer has been found. This doesn’t, however, indicate that you’re destined to develop this type of cancer. It simply means your risk is greater than normal. Conversely, a negative test result doesn’t mean you’re free from the risk of that cancer, but it does indicate you have no increased inherited risk. Finally, not all test results are conclusive. It’s possible that you may have a mutation whose association with cancer is unknown and the mutation probably won’t guide your health care decisions.

No matter the results, a doctor, genetic counselor, or other healthcare professional should help you interpret your genetic test results.

If you think you may have a family history of cancer, talk to your doctor or a genetic counselor. They will help you decide if genetic testing for cancer is right for you.

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Jennifer Klem, PhD