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Do you want to know if you have the "cancer gene"? Part 2 in a 2-part series

  • 03.10.2018

In Part 1 of this series, we looked at what inheriting a specific defective gene associated with cancer means (it doesn’t mean you will get cancer), as well as who should consider genetic testing. In Part 2, we look at the decision-making process for getting a genetic test to assess cancer risk and how to assess test results.

How to decide if you should test

Before making a decision about getting genetic testing, it is strongly recommended that you seek counsel with a genetic healthcare professional, either a doctor or genetic counselor. They can help you weigh and measure the risks, benefits and limitations of testing. Issues you will consider together include:

  1. Is the considered test appropriate for you and will the results be accurate?
    • Test results need to be technically accurate in order to help guide future healthcare decision making.
  2. What are the medical implications of a positive or a negative test result?
    • Knowing may mean needing to act medically in order to try and preserve health.
  3. Will the result be useful in making healthcare decisions?
    • If the test will enable you to make more informed healthcare decisions, it could be of great value. 
  4. What are the psychological risks and benefits of knowing?
    • While a negative test may provide comfort, a positive test could lead to unrelenting anxiety and/or stress.
  5. Do I risk passing a genetic mutation on to children?
    • If you are deemed a carrier, you’ll need to consider the risk of passing the gene on to children.
  6. How will this affect relationships with family members who may not want to know about their own genetic mutations?
    • If one family member decides to test and others don’t want to know their own results, they’ll need to keep their new knowledge private which could strain relations.


Why I tested — to find some control after a cancer diagnosis

With a mother, maternal grandmother and maternal great aunt all with a history of breast cancer, Stephanie U. knew she was at risk. So, she signed up for a high-risk screening program. Her very first MRI revealed cancer. Finding it early meant she didn’t need chemotherapy or radiation, but she worried about her other cancer risks. She decided to have a double mastectomy to treat her existing cancer and prevent future cancer from forming in the other breast. It was after her diagnosis and treatment that she had genetic testing done. “I’m a type A person and I wasn’t used to not being in control,” Stephanie says. “I didn’t want to worry about getting ovarian cancer for the rest of my life. I had a tremendous sense of relief when the test was negative for BRCA.”


What to do with test results

Once you decide to get a genetic test, interpreting and acting on the results is a complicated issue that benefits from the insight and guidance of a genetic counselor. 


Positive test result

A positive test result means the lab found you have the genetic mutation, but what does that mean for you? It could mean a variety of things from an increased risk of developing that cancer to a risk of passing it on to a child to a need for further testing.

Lowering risk: If your test result indicates an increased risk of developing cancer, there may be steps you can take to lower your risk, including more frequent screenings, preemptive surgery and altering personal behavior like smoking.

Pregnancy: A positive result on a prenatal genetic test for cancer risk may influence a decision about whether to continue a pregnancy. The results of pre-implantation testing (performed on embryos created by in vitro fertilization) can guide a doctor in deciding which embryo (or embryos) to implant in a woman’s uterus.

Existing cancer: For someone who already has cancer, a positive test result can influence how the cancer is treated


Negative test result

A negative test result means that the mutated gene has not been passed on to you and you are not a carrier. This is helpful in families where the gene is known to be present. Having a negative result does not mean there is no cancer risk, but rather you have the same risk level as the general population.


This isn’t a time to do it yourself

If you are considering a genetic test for cancer, please work with a trained healthcare professional. While at-home tests are available, they do not come with the support and guidance of a genetic counselor. Without guidance about test results from an informed, genetically knowledgeable healthcare provider, people may experience unneeded anxiety or false reassurance, or they may make important decisions about medical treatment or care based on incomplete information.


If you are facing a cancer diagnosis, exceptional treatment is available in Carson City, South Lake Tahoe, Fallon or Gardnerville, through Sierra Nevada Cancer Center. Same week or sooner appointments are available by calling 775-883-3336.

For current cancer-related health news delivered to your inbox, subscribe to Sierra Nevada Cancer Center’s newsletter.


Read Part 1.





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