Genetic testing after a cancer diagnosis 

A cancer diagnosis can bring a lot of questions. You may wonder what the diagnosis means for your treatment, your future or your family.

Genetic testing may provide helpful answers. Some tests look for changes in cancer cells that can help guide your care. Others look for genetic changes that may run in your family. Your care team can help you understand which tests may be right for you and what the results could mean.  

Why is genetic testing used in cancer care?

Genetic testing is often part of a cancer treatment plan. Depending on the test, the lab may use cancer cells or a sample of your blood or saliva. Your care team may order tests at different points because each one answers different questions.  

The results may help your care team:

• Learn more about your cancer
• Personalize your treatment plan
• Find out if you may have a higher risk of another cancer
• Guide decisions about certain treatments or surgery
• Provide information that may be useful to your family  

There are two main types of testing: biomarker testing and testing for inherited cancer risk. Although the names can sound similar, the tests look for different kinds of genetic changes. 

What is biomarker testing?

Biomarker testing looks for changes found only in the tumor. These changes can affect how the tumor behaves. You may also hear this called genomic testing or molecular testing.

Your cancer provider will order the test. The lab may test tissue from a tumor biopsy or use a blood sample. Once the results are ready, your provider will talk through what they mean and may update your care plan.  

It’s OK if the results feel complicated at first. Your provider can explain what was found, answer your questions and help you understand how the information may shape your care.

What is inherited cancer risk?

Most cancers happen by chance. In some cases, a person is born with a genetic change that raises their risk of developing cancer. This is called an inherited cancer risk. The genetic change can pass from one generation to another.  

Testing may help you make decisions about cancer screening. The results may also guide certain treatment or surgery decisions. If you choose to share your results with relatives, the information may help them decide whether genetic testing is right for them.

Learning about an inherited risk can bring up new questions. A genetic counselor can help you sort through the information and consider what it means for you and your family. 

How can a genetic counselor help?

A genetic counselor is a medical professional with special training in inherited cancer risk. They’ll explain the available tests and talk with you about the possible benefits and risks. They’ll also help you understand your choices and what your results mean.

You don’t have to know all the right questions before your visit. Your genetic counselor can guide the conversation and give you time to talk about what matters most to you.

Genetic counselors are best suited to order tests for inherited cancer risk. In some cases, another member of your care team may order the test.  

What happens during genetic testing?

The process usually includes a few simple steps:

• You meet with a genetic counselor to talk about testing
• You provide a saliva or blood sample. A skin biopsy is rarely needed.
• A lab studies the sample for genetic changes
• You meet with a genetic counselor to discuss your results

Results may take up to three weeks. Your follow-up discussion may happen by phone, video or during another visit. 

What can genetic test results tell you?

Your genetic counselor will explain what your results mean for you. The results may provide information about your cancer risk, treatment choices or screening options. They may also help you consider whether relatives could benefit from testing.

Genetic information can feel like a lot to take in. You don’t have to make sense of it alone. Your genetic counselor and cancer care team can answer questions and help you think through your next steps.

Questions to ask your care team

It can help to bring a list of questions to your appointment. You may want to ask:

• What type of genetic test do you recommend?
• What could the results tell me?
• Could the results affect my treatment?
• What might the results mean for my family?
• How will I receive my results?
• Will I meet with a genetic counselor?
• What should I consider before sharing my results?

Don’t worry if more questions come up later. You can write them down and bring them to your next conversation with your care team.

Common genetic testing terms

Understanding the terminology your care team uses can help ease your anxiety. Here are some common terms used in genetic testing and counseling.

• Biomarker: A substance in the body that can provide information about your health. Normal or abnormal levels may help guide treatment.
• DNA: The genetic information inside the body’s cells. DNA carries instructions for how the body develops and works.
• Genetics: The study of DNA, genes and heredity.
• Inherited: Something that can pass from one generation to another.
• Inherited cancer risk: A higher risk of cancer caused by a genetic change that can run in families.