Patient education: Genetic testing for breast, ovarian, prostate, and pancreatic cancer (The Basics)

What is genetic testing? — Genetic testing is a way to find out if you have certain abnormal genes.

Genes are basically the body's recipe book. They tell your cells how to make different proteins. They also give your body instructions about how you should look and how your body should work. Genes can sometimes have mutations, or what experts call "variants." These are changes in the recipe. They sometimes affect the way your body makes proteins. In some cases, variants can put you at risk for disease.

There are genetic tests that look for variants that are linked to lots of different types of cancer. This article is mostly about BRCA1 and BRCA2 (BRCA1/2). Harmful variants in these 2 genes increase a person's risk of breast and ovarian cancer. They also increase the risk of other hereditary cancers, like pancreatic and prostate cancer. "Hereditary" means related to genes that can be passed down from parent to child.

Why would someone choose genetic testing? — Genes are passed down in families. People who have family members with certain types of cancer sometimes choose to get genetic testing. This way, they can know if they have harmful gene variants. Then, they can figure out whether they need to take steps to lower their risk of cancer.

For people who already have cancer, knowing about their genes can also be useful. It might affect their treatment choices. It might also provide valuable information for their relatives, such as siblings and children.

Should I have genetic testing? — The answer to this question is not the same for everyone. Doctors might recommend BRCA1/2 testing depending on your situation. This includes your:

●Personal history – This means whether or not you have had cancer yourself. The recommendation will depend on:

•How old you were when you were diagnosed with cancer

•What kind of cancer it was

•Whether you have also had relatives with cancer

●Family history – This means whether any of your relatives have had cancer. It will depend on:

•How many people in your family had cancer

•Which relatives they were

•What types of cancer they had

•How old they were when they were diagnosed

•Whether they have tested positive for any genetic variants

●Ancestry – People with Ashkenazi Jewish ancestry (from central or Eastern Europe) have an increased risk of having BRCA1/2 variants. Testing is recommended for people of Ashkenazi Jewish ancestry who have had breast, ovarian, pancreatic, or prostate cancer. People with Ashkenazi Jewish ancestry who have not had cancer can also request testing.

It's important to know that having a strong family history of a disease does not always mean you have abnormal genes. Most people with a personal or family history of cancer do not have an abnormal gene. However, it is possible to have a harmful variant in BRCA1/2 or other genes, even without having a personal or family history of cancer.

If you are thinking about genetic testing because a family member has cancer, ask if they have been tested. If not, you might ask them if they are willing to be tested first. If the person with cancer does not have a harmful gene variant, it might be less likely that you do.

What should I do before I get tested? — Before you get tested, first talk with your doctor or nurse. They can tell you if you should see a specialist. A specialist, such as genetic counselor or a nurse trained in genetics, can help you understand:

●Your risk of cancer and your chances of testing positive

●What the results of testing could mean for you and your family

●What the testing might cost

They will also provide support throughout the testing process.

You can find a list of trained genetic counselors online: www.cancer.gov/about-cancer/causes-prevention/genetics/directory.

What if I test positive for a genetic variant? — If you test positive, try not to worry. It can be scary to learn you have a variant that might increase your risk of cancer. But there are ways to lower the chances that you will get cancer or to find it early.

Ask your doctor and your genetic counselor what your results mean for you. Then ask what you can do to lower your chances of getting cancer or find it early. The table shows the lifetime risk of hereditary cancers for a person with a BRCA1 or BRCA2 variant (table 1).

If you test positive for a genetic variant that increases your cancer risk, tell your family about the results. It might affect their health as well as yours. Some adult family members might also want to get tested.

How can I lower the chances that I will get cancer if I test positive? — There are some things you can do to lower your risk or find cancer early. Doctors have learned a lot about this by studying people with a harmful BRCA1/2 variant. But these options might apply to people with other variants, too.

Options for females:

●Consider extra screening for breast and ovarian cancer, depending on your doctor's recommendations. This will not keep you from getting cancer. But it will increase the odds of finding it early, when it is easier to treat.

●Have surgery to remove your ovaries. To lower your ovarian cancer risk as much as possible, many experts recommend that the ovaries be removed:

•As soon as you are done having children (if you choose to)

•By age 35 to 40 if you have a BRCA1 variant, or age 40 to 45 if you have a BRCA2 variant

Having your breasts removed is also an option, depending on your risks and preferences.

●Take medicines that help lower your chance of getting cancer.

Options for males:

●Consider screening for prostate cancer, depending on your doctor's recommendations.

●Examine your breasts regularly for changes. While it is less common, males can get breast cancer, too.

Depending on your age and situation, and your doctor's recommendations, you might combine several of these choices.

Will my insurance cover genetic testing? — In the US, most health insurance companies cover most of the costs. But your doctor or genetic counselor might need to write a letter to the insurance company to explain why you need testing.

Can the results of my test keep me from getting health insurance? — No. In the US, there is a law that prevents most companies from using a person's genetic tests to make decisions about insurance coverage or employment.

The law means that:

●Most employers can't deny you a job or fire you because of the results of genetic tests

●Health insurers can't use genetic test results to deny you coverage or set your insurance rates

●Employers and insurers can't force you to have genetic tests

It's important to know that the law does not say anything about long-term care, disability, or life insurance. In other words, if you have a genetic variant, insurers can choose to deny you these types of coverage.

More on this topic

Patient education: Breast cancer (The Basics)
Patient education: Breast cancer screening (The Basics)
Patient education: Ovarian cancer (The Basics)
Patient education: Ovarian cancer screening (The Basics)
Patient education: Breast reconstruction after mastectomy for cancer (The Basics)

Patient education: Breast cancer guide to diagnosis and treatment (Beyond the Basics)
Patient education: Genetic testing for hereditary breast, ovarian, prostate, and pancreatic cancer (Beyond the Basics)
Patient education: Factors that affect breast cancer risk in women (Beyond the Basics)
Patient education: Breast cancer screening (Beyond the Basics)
Patient education: Medications for the prevention of breast cancer (Beyond the Basics)
Patient education: Screening for ovarian cancer (Beyond the Basics)