The Role of Genetic & Genomic Testing In Cancer Treatment

Genetic & Genomic Role in Cancer Treatment.

In the context of cancer testing, “genetics” and “genomics” are often used interchangeably, which is why these two terms are often thought to be synonymous. Interestingly, they are not the same although both involve testing genes they have different purposes and applications.
It’s interesting to note that there are more than 77,000 medical genetic tests that are currently used and more being developed. They are used for evaluating diseases in many kinds of situations. This blog is limited to the role both genetic and genomic testing has in cancer treatment.


Cancer used to be one size fits all. In the past, each type of cancer would get the same treatment of chemo or radiation. Today’s objective is to provide precision medicine based on the analysis of a tumor. The genomic tests provide, in many cases, the information on how the actual tumor is “behaving” …how fast it might grow, spread, or if it is similar to other previously treated tumors. This will determine the right treatment. Basically, it looks at all your genes that make up your thread to determine your “DNA Sequencing”.

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Cancer genetics testing is useful to determine the possibility of inheriting genes of a blood relative with cancer. It is designed to detect a specific single gene mutation like BRCA 1 and 2. Having this knowledge allows the medical team to determine the risk of cancer and develop a monitoring program for early detection.


Either test should not be considered without detailed discussions with your medical team and genetic specialists. It is strongly suggested that all tests be scheduled by your medical team.

Cancer genomic testing is ideal for a person with cancer that has not responded to treatment. This test is used to determine if one has resistance to certain treatments, and how to reduce the risk of side effects from a treatment. A cancer genomic test will guide your medical team on deciding if it is beneficial to participate in clinical trials. Lastly, this test will determine a follow up treatment and the risk of recurrence.

Cancer genetic testing is done by completing a Cancer Family History Chart for blood relatives. This is critical for your medical team to assess the pattern of cancer in your family if any.

Generally, if the answers are yes to all or most of the risk factors below, your doctor or genetic counselor may advise you to come in for genetic testing:


  • Do you have a family history of cancer?
  • Do you have close relatives who developed cancer at an early age?
  • Do you have a family history of multiple cancers? 
  • Do you have a family history of rare cancers?

It is important to note that genetic testing will not be able to fully determine if you will actually develop cancer, but it will tell if you are at higher risk.


Before being tested, be sure you have a complete understanding of the risks involved and your reasons for wanting a test. It is also helpful to think about how you will cope with the results.


To Relieve uncertainty. Testing information may relieve the anxiety and uncertainty of not knowing your gene status. For some people, knowing is better than not knowing. 


Testing may cause depression, anxiety, or guilt. If a person receives a positive test result (meaning a mutation exists) it may cause anxiety or depression about the possibility of developing cancer. Some people may think of themselves as sick, even if they never end up developing cancer. If a person does not have a mutation but members of the family do, they may experience feelings of guilt.


Genomic Testing is typically conducted by taking a biopsy from the tumor. Sometimes blood is drawn from the tumor. These samples are sent to a special lab to profile the structure of the tumor.


If you and your oncologist decide you are a candidate for genomic testing, here’s how the process would work:


  • biopsy will be taken of your tumor or saliva sample.
  • Cancer cells will be isolated and extracted from the biopsy, then their DNA will be sequenced in the lab.
  • Highly sophisticated equipment will be used to scan the sequenced genetic profile for abnormalities that dictate how the tumor functions.
  • The abnormalities will be analyzed in a lab to determine whether they match known mutations that may have responded to therapies or where evidence suggests there may be a potential treatment option not previously considered.
  • If there’s a match, your oncologist may be able to use the results to suggest treatments that have been used in the past to target the same mutations.
  • Your oncologist will explain the results to you and any indications for new treatment options, and together you will formulate a treatment plan targeted to your individual situation.
  • If you or your caregivers have additional questions, we will offer resources and educational guidance on this emerging field of medicine.


Genetic testing is most commonly performed by extracting a vile of blood. Sometimes saliva is used. The sample is sent to a special lab to evaluate your genes.


After the samples are extracted it takes independent private labs 2 to 3 weeks to complete the analysis and report back to your medical team. Sometimes the samples are sent to research centers for special evaluation which will take much longer.


In many cases, health insurance plans will cover the costs of genetic testing when it is recommended by a person’s doctor. Health insurance providers have different policies about which tests are covered. However, it may be best to contact the insurance company before testing to ask about coverage.


Some people choose not to use their insurance to pay for testing. Instead, they opt to pay out of pocket for the test or pursue direct-to-consumer genetic testing to avoid genetic discrimination. Therefore, you may want to find out more about your state’s privacy protection laws before asking the insurance company to cover the costs.


Genetic and Genomic testing is becoming more critical related to cancer treatment evaluation. Each test is designed to provide different information to your medical team. Results from Genetic Cancer tests will indicate if you have inherited a cancer gene from a blood relative. Genomics test findings will help your medical team develop “precision medicine” to treat your type of cancer. However, before agreeing to have a test done it is vital that one clearly understands the benefits, risks, and costs.

This information is intended as general information only. It was not written or intended as a substitute for medical advice. Please seek professional advice from your physician before taking any action that could affect your health.