Answers to 5 questions about genetic testing for ovarian cancer

By Sharon Doering-Domanus

Early ovarian cancer is often symptomless. When symptoms develop, they can be vague or mimic an upset stomach, so ovarian cancer often goes undetected until it has spread within the abdomen. At this advanced stage, ovarian cancer is more difficult to treat.

More than 19,000 women will be diagnosed with ovarian cancer this year in the U.S., according to the American Cancer Society. While ovarian cancer is not common, it accounts for more deaths than any other cancer of the female reproductive system. Some people have a higher risk for ovarian cancer because they inherited a gene that raises their cancer risk from one of their parents.

Inherited genes cause about 20%–25% of ovarian cancers. You can get a blood test to find out if you were born with a gene that raises your risk of ovarian cancer.

Casey Swanson, a Mayo Clinic physician assistant specializing in hereditary ovarian cancer, answers the most common questions she hears from people about genetic testing for ovarian cancer:

1. How much do hereditary genes raise your risk?

The National Comprehensive Cancer Network recognizes 11 genes that increase the risk of developing ovarian cancer: BRCA1, BRCA2, BRIP1, MLH1, MSH2, MSH6, PMS2, EPCAM, PALB2, RAD51C and RAD51D.

Each of these 11 genes carries a different lifetime risk of developing ovarian cancer. Depending on the gene, this risk ranges from 3% to 45%. It's important to know that having a gene that raises your risk does not mean you will definitely get ovarian cancer.

Most ovarian cancer cases are not inherited. They are the result of random genetic changes that accumulate throughout your life. Everyone accumulates these genetic changes throughout life, which is one reason most cancers develop later in a person's lifetime.

Most women diagnosed with ovarian cancer, whether their cancer's origin was a hereditary gene they were born with or a genetic change that occurred later in their lives, are older than 55.

2. Who should consider genetic testing for ovarian cancer?

Not everyone needs to get tested. Only when diseases are common do health care professionals recommend regular screening for everyone.

For example, a woman's risk of getting breast cancer is 1 in 8, so Mayo Clinic health care professionals recommend all women get a mammogram yearly, starting at age 40.

A woman's risk of getting ovarian cancer during her lifetime is 1 in 78, so routine screening for most women is unnecessary.

Mayo Clinic health care professionals recommend genetic testing for ovarian cancer in these specific cases:

• If you are diagnosed with any cancer.
• If one of your first-degree relatives, such as parents, siblings or children, learns they have a gene that raises their cancer risk.
• If one of your first-degree relatives is diagnosed with ovarian cancer.

If you have a relative with a hereditary ovarian cancer gene but you are under 18, health care professionals recommend you wait to get genetically tested until you are at least 18. Most cases of hereditary and nonhereditary ovarian cancer do not develop in women under 40.

3. What are the benefits of knowing you have a gene that raises your cancer risk?

You can take small steps to reduce your overall cancer risk. Lifestyle changes, including increasing your intake of fruits and vegetables, adding exercise, and reducing your alcohol consumption, can reduce your risk of several types of cancer.

Other things that may decrease your chance of developing ovarian cancer are using oral contraceptive pills, tubal ligation, breastfeeding or having children. Knowing what reduces your risk of ovarian cancer can help you make informed choices.

You can choose preventive surgery. If you are at a higher risk for ovarian cancer, talk to your health care professional and a genetic counselor about risk-reducing surgery. Surgery to remove your ovaries and fallopian tubes may be recommended for high-risk women after they have children. These operations significantly lower your risk of ovarian cancer.

4. What are the drawbacks of knowing you have a gene that raises your cancer risk?

The drawbacks of knowing you have a gene that raises your cancer risk are:

Fear and anxiety

Sometimes knowing you are at a higher risk for a disease can cause psychological stress. Talking to a genetic counselor or joining a support group for people in a similar situation can ease your fear.

Feeling pressured to make fertility decisions

Young women who haven't yet decided whether they want to have children may feel pressure to make fertility decisions earlier than they would have if they hadn't known their risk. People have a 50% chance of passing on a cancer-linked gene to their offspring. A woman might worry about passing the cancer gene onto her child, making fertility decisions more stressful.

Women who have a hereditary risk of ovarian cancer should not feel rushed to remove their ovaries if they want to have children naturally. They should attempt to have children when it fits into their lives. Remember, even if you have a gene that raises your risk of ovarian cancer, your risk of developing that cancer before 40 is low.

5. What if you learn you have a hereditary gene that raises your cancer risk?

If you learn you have a hereditary gene that raises your cancer risk, you should:

Share your health history.

After you learn about a hereditary ovarian cancer gene, it is recommended that all first-degree relatives meet with a genetic counselor to discuss testing. Sharing your health history with your family can help them and their children make informed choices.

Get appropriate cancer screening.

Talk to your health care professional about adding routine cancer screening to help you optimize your long-term health.

Consider your situation.

Genetic counselors' recommendations are personalized based on a woman's age, specific cancer gene, childbearing status and ongoing cancer treatment. If a risk-reducing surgery is recommended, a counselor follows National Comprehensive Cancer Network guidelines to determine at what age the woman should have surgery to remove her ovaries and fallopian tubes. If you would like to discuss your fertility options, a genetic counselor can refer you to a reproductive endocrinology and infertility team.

Manage your risk.

Remember that having a hereditary gene that raises your ovarian cancer risk does not mean you will get ovarian cancer. Genetic testing is a tool for understanding your health risks. Knowing you are at a higher risk for ovarian cancer can help you reduce your risk.

Before deciding on genetic testing, consider talking with a genetic counselor. Genetic counselors can provide important information and support, assist with testing decisions, help prepare you for test results and interpret those results, provide access to support groups, discuss insurance concerns and navigate insurance approval. If testing identifies a hereditary cancer gene, genetic counselors also can support you in talking to your family members.

Learn more

Learn more about ovarian cancer and genetic testing, and find an ovarian cancer clinical trial at Mayo Clinic.

Also read these articles:

• "BRCA gene test for breast and ovarian cancer risk."
• "Ovarian cancer is hard to detect, but new and better treatments are improving survival."