Genetic Testing to Understand Your Family History

Cancer can appear in families. If more than one relative has had it, and especially if it showed up earlier than expected, you might ask if a shared gene change is involved. Genetic testing can give you clarity about inherited gene changes. It can also support you and your care team as you decide on checkups and ways to lower risk.

Having genetic testing does not mean you will get cancer. It only tells you whether you carry certain inherited changes. Some of these changes can increase the risk of certain cancer types.

What Is Genetic Testing?

Genetic testing checks DNA. These are sometimes called mutations or variants. Some changes are passed down by a parent. That is how they can travel through a family.

BRCA1 and BRCA2 are common examples. Changes in these genes can raise risk for breast and ovarian cancer. They can also relate to prostate and pancreatic cancer, along with a few other types. There are also inherited changes linked with Lynch syndrome. With Lynch syndrome, the risk of colorectal cancer can be higher. Other cancers may also occur more often.

This testing is not the same as testing a tumor. Tumor tests focus on changes found in cancer cells. Inherited testing looks for changes that may be in many cells across the body. Those findings can also affect what you might pass on to your children.

Family history and cancer risk

Family history can point to patterns. It can show whether cancer appears in your family more than expected by chance. Clinicians check several things. They look at who was affected. They note the type of cancer. They also record the age when the diagnosis was made.

You should consider speaking with a health professional if the same cancer comes up more than once in close relatives. This also applies if related cancers show up in multiple people. Mention it if a person was diagnosed at a very young age. Bring it up if someone has more than one cancer. Also discuss it if the family has a rare cancer.

Keep in mind this key point. Having cancer in a relative does not always mean it was inherited. In many cases, cancers are not caused by a genetic change passed through families.

Who should think about genetic testing?

Genetic testing is sometimes suggested when a person has a certain personal history or family pattern. This can include someone diagnosed earlier than expected. It can also include someone who has had more than one type of cancer. Sometimes doctors look at cancers that are linked to inherited gene changes.

Testing may also be discussed when several close relatives had the same or related cancers. Timing can be important too, especially if the diagnoses happen at younger ages. A healthcare provider or a genetic counselor can go over your family history with you. They can also help you decide whether genetic testing fits your situation.

What Happens During Genetic Testing?

First, you often talk with a genetic counselor or another trained health professional. They ask about your own health and your family history. They also explain what the test can show and what it cannot. Next comes the test. For many tests, it is simple. Your clinician may take samples such as blood, saliva, or another body tissue. Then the sample goes to a lab. After the lab finishes, you get the results. When you receive the report, your clinician or counselor goes over it with you. They also talk about what you might do next based on what the results say.

What can you do with test results?

A major value of genetic testing is that it can shape next steps for your care. Sometimes the results lead to a higher inherited chance of certain cancers. In that case, your care team may advise you to start screening sooner. They may also suggest doing those screenings more often. What they recommend can vary by the gene involved and by your personal situation. Your team might also talk about prevention steps. There is also a family side to these results. If you carry an inherited gene change, relatives may choose to talk with a clinician. They can ask whether genetic testing would make sense for them.

Genetic Counseling Is an Important Step

Genetic testing can bring up tough issues. This is especially true when the results could touch other people in your family. Counseling gives you room to sort out what testing might help with. It can also clarify what testing cannot answer. You get to do this before you choose to go forward. A genetic counselor can also help you lay out your family health history. You can discuss which tests fit your situation. You can look over what results might be like. Then the counselor can walk you through what the findings could mean for you and for other relatives.

What Should You Know Before Testing?

Before you order a test, pause and think for a bit. Also think about how you might react if the results come back in different ways. One more point matters. A genetic test cannot say for sure if a person will get cancer. The chance of cancer depends on many things. Genetics play a role, but so do age, diet and habits, time, life conditions, and random events.

Bottom Line

Family cancer history can offer clues about your own chances of getting cancer. If more than one relative has had cancer, especially when they were young, you may want to ask your doctor about genetic counseling or testing. Testing cannot guarantee what will happen to you. What it can do is show whether there are inherited gene changes. That information may help you and your care team choose screening plans, prevention steps, and other care choices.

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