Personalized medicine is a new way to find the right treatment for each patient based on the person's genes (or the genes in their cancer cells).
One approach in personalized medicine is genomic tumor testing. This testing uses information from the genes in your cancer cells to help doctors put together a plan for care that usually involves very specific information. Test results show which treatment is likely to work best for you based on your specific cancer and the genes in your cancer cells.
This approach is a change from the past. For example, years ago, everyone with stage three lung cancer received the same treatment. It probably included some combination of surgery, chemotherapy, and radiation. Today, doctors know more about cancer, including what causes cancer to grow and divide uncontrollably. Doctors are now able to use information about what’s going on inside cancer cells to learn the best way to treat the disease.
There are many terms doctors may use when creating a personalized approach to treating your cancer. They might not use the exact words "personalized medicine" or "precision medicine." Instead, they might talk to you about genetic, genomic, DNA, or molecular testing. Or they might discuss looking for biomarkers or getting a genetic profile.
Personalized medicine is only available for certain types and stages of cancer at this time, but many personalized therapies are currently being studied in clinical trials and may be available for more cancer types in the future.
What do genes have to do with cancer?
Cancer is a genetic disease—that is, cancer is caused by certain changes to genes (called variants) that control the way our cells function, especially how they grow and divide.
Genes play an important role in who we are. They affect the way our cells and bodies work. Genes are found inside of cells and are made of DNA. They can be passed down through families.
Genes also hold clues to our health. In cancer, the genes that make up one person’s tumor can be very different from the genes of another person’s tumor. In other words, cancer genes vary from person to person. Genes can change, and a change in a gene is called a variant. Some variants can lead to cancer. There are two types of variants: those that happen in our lifetime (acquired variants) and those that are passed down through families (inherited variants).
Genomic variants that develop during your lifetime are acquired variants. They occur as you get older and are the result of the wear and tear of life, the environment around you, and sometimes, lifestyle choices. You do not inherit them from your parents and you cannot pass them on to children. Acquired variants are not found in all of your cells - sometimes, there may be acquired variants in just cancer cells. These can affect how cancer grows and spreads.
Some variants are passed down through families; they are inherited. These variants came from your parents and can be passed on to your biological children. Some inherited variants may increase your risk of getting cancer. You may hear them described as genes that cause cancer. In fact, it is the change or variant in the gene — not the gene itself — that can increase the risk of cancer.
What is genomic tumor testing?
Genomic tumor testing is used to find genomic variants that exist in cancer cells. Some of these variants may play an important role in how the cancer grows, spreads and responds to treatment. Therefore, genomic tumor test results can sometimes help doctors choose the right medicines to treat your cancer.
What is the difference between genomic tumor testing and hereditary cancer testing?
Hereditary cancer testing looks for changes in a person’s DNA profile that were inherited from their parents. Genomic tumor tests analyze the variants in cancer cells. Both tests may be helpful in treating cancer. However, hereditary and genomic tumor testing are used in different ways and in different circumstances.
In cancer care, hereditary testing is used to look for genetic variants that a given person inherited from their parents. These variants put people at an increased risk of developing cancer. For example, those who test positive for the BRCA1 gene variant have a higher risk of developing breast, ovarian and prostate cancers.
Genomic tumor testing is used to identify variants that are not inherited but instead occur within the cancer cell itself, often due to an external cause, such as tobacco use or sun exposure. These variants may determine why the tumor behaves the way it does (why it grows or spreads, for example) and may be used to determine the best treatment for your cancer.
How is genomic tumor testing done?
Genomic tumor testing is usually done on tissue that was already collected and stored as part of your medical care. If a sample of tumor is not available for genomic testing, sometimes it's possible to do a test using a blood sample. In this test, a lab looks for tumor cells that came loose from the tumor and are circulating in the blood. Your doctor will get a report about the variants found with genomic tumor testing. You and your doctor will then decide how to use the information to guide your care.
What are the benefits of genomic tumor testing?
The results of genomic tumor testing may provide information on how your cancer is expected to act, and may help you and your doctor decide how to treat your cancer.
Are there risks to genomic tumor testing?
There is a possibility that knowing the results from your genomic tumor test may cause you to feel anxious, disappointed or upset. This is because one or more of the following things could happen:
The test result may not be helpful in deciding which medicines to use.
The test result may identify genomic variants that have uncertain meaning or significance for your treatment.
The test result may identify genomic variants that cannot be treated.
The test result may suggest a medicine that is not covered by your insurance.
The test result may suggest a clinical trial that is only available at a hospital a distance from your home.
The test result may suggest you have a genomic variant that you inherited from one of your parents. If your doctor is concerned about this, you may need another blood draw for hereditary genetic testing. Your doctor sometimes orders this test, or you may be referred to a genetic counselor.
If an inherited genomic variant is found, some of your relatives may have inherited this variant and may be at an increased risk for cancer.
How do I learn more about genomic tumor testing and personalized medicine?
Ask your doctor about genomic tumor testing and whether it might be right for you.