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Hereditary Breast and Ovarian Cancer Syndrome

Medically reviewed by Last updated on Aug 31, 2022.

What is hereditary breast and ovarian cancer syndrome (HBOCS)?

HBOCS is a condition that increases your risk for breast cancer and ovarian cancer. One or both types of cancer will run in your family. You may notice some unusual features of these cancers that occur in your family members. For example, cancer may be found at an earlier age than expected. Breast cancer may be found in both breasts in one person. One woman may also develop both breast and ovarian cancer. Breast cancer may occur in male members of your family. HBOCS does not mean you will definitely develop one or both cancers. You can still make healthy lifestyle choices to help lower your risk if tests show you have HBOCS.

What causes HBOCS?

  • Certain cancers grow because of mutations (changes) in genes that are supposed to control cell growth. These genes are called tumor suppressor genes because they suppress (stop) cancer cells from growing. Mutations keep them from being able to do this. Many genes can cause HBOCS. The most common genes involved are breast cancer 1 (BRCA1) and breast cancer 2 (BRCA2).
  • HBOCS happens because the mutations can be passed down through generations of a family. You have 1 copy of these genes from your mother and 1 copy from your father. They can work to prevent cancer cells from growing as long as 1 copy is normal. HBOCS means that you were born with 1 mutated copy and the other copy has become mutated.

How is HBOCS diagnosed?

  • Your healthcare provider will talk to you about your family cancer history. The genes that can cause HBOCS may come from either your mother or your father. Tell your provider about all the members of both sides of your family who had any type of cancer. This includes men in your family who have had breast cancer. Be sure to tell your provider about any members who have had prostate, pancreatic, melanoma (skin), or uterine cancer.
  • Your provider may refer you to a genetic counselor. This is a specialist who will go through your family history and talk to you about your risk for HBOCS. Anyone can have a BRCA1 or BRCA2 mutation. Your risk is higher if your ancestry is European (Ashkenazi) Jewish, French Canadian, or Icelandic. Tell your genetic counselor if you know about your ancestry.
  • You may decide to be tested for HBOCS. Tell your genetic counselor if anyone in your family currently has breast or ovarian cancer. It is best to have that person tested first, if possible. This can help find a genetic mutation if one exists. If no one is available for testing but you are in a high-risk group, you can still be tested. You will need to give a blood or saliva sample. You will get the results in about a month.
  • Your genetic counselor will talk to you about what the results mean for you and your family members. This includes current family members, such as your brothers or sisters, who may also have the gene mutation. It also includes your current children who may be at risk, and children you may pass the mutation to in the future.

How does a BRCA mutation increase my risk for breast and ovarian cancers?

  • Breast cancer risk: The risk for developing breast cancer by age 70 is 57% for BRCA1 carriers and 49% for BRCA2 carriers. This is compared with 7% for the general population. The risk for developing both breast and ovarian cancer is 12.7% for BRCA1 carriers and 6.8% for BRCA2 carriers.
  • Ovarian cancer risk: The risk for developing ovarian cancer by age 70 is 39% to 46% for BRCA1 carriers and 10% to 27% for BRCA2 carriers. This is compared with 1.8% for the general population.

What are the benefits and risks of genetic testing?

  • Benefits:
    • If you do have a gene mutation, you may be able to start screening earlier than is usually done. This can help find breast or ovarian cancer in an early stage. Cancer treatment is often more successful when it starts early. This means you can make more decisions about treatment. You may also be able to help family members get tested early.
    • If you do not have a gene mutation, testing can be a relief if breast or ovarian cancer runs in your family. You could still develop cancer, but your risk is the same as any woman's who does not have a BRCA mutation. You may also feel relief to know that you will not pass the mutated gene to your children.
  • Risks:
    • If you do have a gene mutation, you will have to decide whether to tell family members about your test results. You may feel anxious or depressed if you are at an increased risk for developing cancer. You may spend years worrying about cancer that never develops. You may also worry about your children or other family members who are at risk.
    • If you do not have a gene mutation, you may feel guilty if tests show you are not at risk but other family members are.

What may healthcare providers recommend to help me prevent breast and ovarian cancer?

  • Surgery is the most effective way to prevent breast and ovarian cancers. Talk with your family and your healthcare providers about all the risks and benefits of surgery. Surgery can be overwhelming and scary. You will want to make sure you are comfortable with your decisions. The following are types of surgeries that can be done to prevent breast and ovarian cancers:
    • Removal of both breasts reduces the risk for breast cancer by 85% to 100%. Usually healthcare providers recommend having both breasts removed. This surgery is usually done along with breast reconstruction. Talk to your healthcare provider about reconstruction options. Reconstruction means giving shape back to your breast area to make it appear like your natural breast.
    • Removal of both ovaries and fallopian tubes may prevent ovarian cancer. If done before you are in menopause, this surgery can also reduce your risk for breast cancer. This surgery may be right for you if you are 35 to 40 years of age and do not want to have more children.
  • Have screening as directed. Your healthcare providers will tell you how often to have screening tests. Screening can help find cancer when it is at an early stage. This can make it easier to treat. Screening can give false-negative or false-positive results. This means tests may show you have cancer when you do not, or tests may not show cancer that you do have. Talk with your healthcare providers about all the screening tests available and what you can expect.
    • Screening for breast cancer includes a breast exam every 6 to 12 months. Your provider may also recommend that you start having a breast MRI every year from age 25 to 29. Then you may need to have both an MRI and a mammogram every year starting at age 30.
    • Screening for ovarian cancer may include checking for high levels of a protein called CA 125 in your blood. This can be an early sign of ovarian cancer. Your provider may also use an ultrasound to check your ovaries for changes or signs of cancer. These tests may start before you are 30 years old.
  • Medicines may be used to prevent cancer. For example, certain birth control pills can help lower your risk for ovarian cancer. Breast cancer risk-reducing medicines are also available.

What can I do to reduce my risk for breast and ovarian cancers?

  • Do not smoke. Nicotine and other chemicals in cigarettes and cigars can increase your risk for cancer. Ask your healthcare provider for information if you currently smoke and need help to quit. E-cigarettes or smokeless tobacco still contain nicotine. Talk to your healthcare provider before you use these products.
  • Do not drink alcohol. Alcohol increases the risk for new or returning cancer. Talk to your healthcare provider if you currently drink alcohol and need help to quit.
  • Eat a variety of healthy foods. Healthy foods include fruits, vegetables, whole-grain breads, low-fat dairy products, beans, lean meats, and fish. Ask if you need to be on a special diet.
  • Maintain a healthy weight. Extra weight can increase your risk for cancer. Talk to your healthcare provider if you are overweight. He or she can help you create a healthy weight loss plan.
  • Exercise as directed. Ask your healthcare provider about the best exercise plan for you. Exercise can help you manage your weight.
    Walking for Exercise

Where can I find support and more information?

  • American Cancer Society - Genetics and Cancer
    250 Williams Street
    Atlanta , GA 30303
    Phone: 1- 800 - 227-2345
    Web Address:
  • National Cancer Institute - Cancer Risk and Genetic Testing
    6116 Executive Boulevard, Suite 300
    Bethesda , MD 20892-8322
    Phone: 1- 800 - 422-6237
    Web Address:

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