Hereditary Breast and Ovarian Cancer

Approved by the Cancer.Net Editorial Board, 11/2015

What is Hereditary Breast and Ovarian Cancer?

A diagnosis of Hereditary Breast and Ovarian Cancer Syndrome (HBOC) should be considered when there are multiple cases of breast cancer and/or ovarian cancer on the same side of the family. The chance that a family has HBOC increases in any of these situations:

  • One or more women are diagnosed at age 45 or younger

  • One or more women are diagnosed with breast cancer before age 50 with additional family history of cancer, such as prostate cancer, melanoma, and pancreatic cancer

  • There are breast and/or ovarian cancers in multiple generations on the same side of the family, such as having both a grandmother and an aunt on the father’s side both diagnosed with these cancers

  • A woman is diagnosed with a second breast cancer in the same or the other breast  or has both breast and ovarian cancers

  • A male relative is diagnosed with breast cancer

  • There is a history of breast cancer, ovarian cancer and/or pancreatic cancer on the same side of the family

  • There is a history of breast and/or ovarian, pancreatic, or male breast cancer in a family of Ashkenazi Jewish ancestry

What causes HBOC?

HBOC is an inherited genetic condition. This means that the cancer risk is passed from generation to generation in a family. Two genes are associated with the majority of HBOC families: BRCA1 and BRCA2. BRCA stands for BReast CAncer. Other, less common genes have also been associated with an increased risk of developing breast and other cancers, such as mutations in the TP53, PTEN, CDH1, ATM, CHEK2 or PALB2 tumor suppression genes and many others. Blood tests now include many of these genes in a single, multiple-gene panel test. A mutation (alteration) in either BRCA1 or BRCA2 gives a woman an increased lifetime risk of developing breast and ovarian cancers. Men with these gene mutations also have an increased risk of breast cancer and prostate cancer.  There is a slight increase in the risk of other cancers including pancreatic cancer and melanoma among carriers of BRCA1 or BRCA2 mutations. Not all families with multiple cases of breast and ovarian cancer have mutations in BRCA1 or BRCA2.

How is HBOC inherited?

Normally, every cell has 2 copies of each gene: 1 inherited from the mother and 1 inherited from the father. HBOC follows an autosomal dominant inheritance pattern, in which a mutation needs to happen in only 1 copy of the gene for the person to have an increased risk of getting that disease. This means that a parent with a gene mutation may pass along a copy of their normal gene or a copy of the gene with the mutation. Therefore, a child who has a parent with a mutation has a 50% chance of inheriting that mutation. A brother, sister, or parent of a person who has a mutation also has a 50% chance of having inherited the same mutation. 

Options exist for couples interested in having a child when they know that one of them carries a gene mutation that increases the risk for this or any other hereditary cancer syndrome. Preimplantation genetic diagnosis (PGD) is a medical procedure done in conjunction with in-vitro fertilization (IVF). It allows both women and men who carry a specific known genetic mutation to have children who do not carry the mutation. A woman’s eggs are removed and then fertilized (in a laboratory setting) with sperm. When the embryos are only 8 cells in size (very early in the development process), one cell is removed and is tested for the hereditary condition in question. The future parents can then choose to transfer the embryos without the mutation to the woman’s uterus. PGD has been in use for over a decade, and more recently has been used for several hereditary cancer predisposition syndromes. However, this is a complex procedure with financial, physical, and emotional factors to consider before starting. For more information, talk with an assisted reproduction specialist at a fertility clinic.

How common is HBOC?

Most breast and ovarian cancers are sporadic, meaning they occur by chance with no known cause. Most women who have breast or ovarian cancer do not have HBOC.

Current estimates are that less than 1% of the general population has a mutation in the BRCA1 or BRCA2 genes, and only 10% to 15% of women diagnosed with breast cancer have a mutation in one of these genes. About 10% to 30% of women under the age of 60 diagnosed with “triple-negative” breast cancer, which are cancers that do not have receptors for estrogen, progesterone and HER2/neu, will have a BRCA1 or BRCA2 gene mutation, and others will have mutations in related breast cancer risk genes; therefore international guidelines recommend that these women be referred for genetic counseling and genetic testing (see below). HBOC is most frequently diagnosed when there are multiple cases of breast cancer and/or ovarian cancer on the same side of the family. In families with 4 or more cases of breast cancer diagnosed before age 60, the chance of HBOC is approximately 80%. To compare, the chance of finding HBOC when only 1 woman has had breast cancer diagnosed under age 50 is estimated to be 10% or less.

Individuals with Ashkenazi Jewish ancestry have an increased chance of having HBOC.  Three specific gene mutations, known as “founder mutations,” are common in this population:

  • 185delAG in BRCA1 (also reported as 187delAG)

  • 5382insC in BRCA1

  • 6174delT in BRCA2

It is estimated that about 1 in 40 individuals with Ashkenazi Jewish ancestry has 1 of these 3 mutations. Approximately 1 in 10 women with breast cancer and 1 in 3 women with ovarian cancer in Ashkenazi Jewish families have 1 of the BRCA1 or BRCA2 gene mutations. If a person is found to have a BRCA2 mutation, it is important for the other prospective parent to also be tested prior to pregnancy. This is particularly true for those of Ashkenazi Jewish ancestry in whom the risk of having the mutation is higher (see next section). If both parents carry a BRCA2 gene mutation, there is a 25% risk with each pregnancy of having a child with Fanconi anemia, which is an inherited disorder, associated with physical abnormalities, an increased risk of blood cancers, and other serious problems. Fanconi anemia is inherited in an autosomal recessive pattern, meaning that if a child inherits a copy of the BRCA2 gene with a mutation from each parent, he or she will be born with the disease.

For women with a previous diagnosis of breast or ovarian cancer and/or a family history of breast or ovarian cancer, the National Comprehensive Cancer Network (NCCN) provides recommendations regarding whether genetic counseling and testing are recommended. The phrase “first-degree relatives” include parents, siblings, and children. “Second-degree relatives” include aunts/uncles, grandparents, grandchildren, and nieces/nephews. “Third-degree relatives” include first-cousins, great-grandparents, or great-grandchildren. Genetic testing should be considered if a person or family meets 1 or more of the criteria listed below:

  • A family member has a known mutation in the BRCA1 or BRCA2 genes or other related breast cancer risk genes

  • A personal history of breast cancer plus 1 or more of the following:

    • A diagnosis of breast cancer at age 45 or younger

    • A diagnosis of breast cancer at age 50 or younger with:

      • A diagnosis of a second breast cancer in the same or the other breast

      • 1 or more first-, second-, or third-degree relatives on the same side of the family with breast cancers regardless of age at diagnosis

  • A diagnosis at age 60 or younger with triple-negative breast cancer (see above)

  • A breast cancer diagnosis regardless of age and:

    • 1 or more first-, second-, or third-degree relatives on the same side of the family with breast cancer diagnosed at age 50 or younger

    • 2 or more first-, second-, or third-degree relatives on the same side of the family with breast cancer diagnosed at any age

    • 1 or more first-, second-, or third-degree relatives on the same side of the family with invasive ovarian cancer

    • 2 or more first-, second-, or third-degree relatives on the same side of the family with a diagnosis of prostate cancer and/or pancreatic cancer regardless of age at diagnosis

    • A history of breast cancer in a male relative

    • Being in a family of Ashkenazi Jewish ancestry

    • A personal history of ovarian cancer

    • A personal history of male breast cancer

    • A personal history of prostate cancer regardless of age, with 1 or more first-, second-, or third-degree relatives on the same side of the family with breast cancer diagnosed at age 50 or younger, and/or invasive ovarian cancer, pancreatic cancer, or prostate cancer diagnosed at any age.

    • A personal history of pancreatic cancer regardless of age, with 1 or more first-, second-, or third-degree relatives on the same side of the family with breast cancer diagnosed at age 50 or younger, and/or invasive ovarian cancer and/or pancreatic cancer diagnosed at any age.

    • A personal history of pancreatic cancer and a family history of Ashkenazi Jewish heritage

Based on Family history Only:

  • A first- or second-degree relative on the same side of the family who meets any of the criteria listed above

  • A third-degree relative on the same side of the family who has breast cancer and/or invasive ovarian cancer with 2 or more relatives with breast cancer diagnosed at age 50 or younger, and/or invasive ovarian cancer

How is Hereditary Breast and Ovarian Cancer (HBOC) identified?

Families with multiple women diagnosed with breast cancer before age 50 and families with both breast and ovarian cancers might be at risk for having HBOC. Mutations in the BRCA1 or BRCA2 genes can be identified through a blood or saliva test. Since most breast and ovarian cancers are sporadic, meaning that cancer occurs by chance with no known cause, genetic testing is recommended primarily for people who have a personal and/or family history that suggests HBOC. While standard gene sequencing identifies the majority of mutations, there are other types of mutations called rearrangements, which include deletions or duplications, in BRCA1 and BRCA2 that also may cause an increased risk for these cancers. Testing for large rearrangements in BRCA1 and BRCA2 is now available. If the result of your initial BRCA1 and BRCA2 genetic testing was negative, meaning no mutation was detected, or a variant of uncertain significance was identified, there may be additional testing that is recommended. Talk with your doctor or genetic counselor for more information. Most, but not all, insurance companies are now covering the cost of complete BRCA1 and BRCA2 testing, including Medicare and Medicaid. Many genetic specialists are now offering testing that includes multigene panels and may offer additional insight. These panel tests may include 6, 20, 40 or more genes depending on the personal and family history. The multigene panel tests may often be ordered at the same time as BRCA1 and BRCA2 testing. You should discuss this information with your genetic counselor. If a mutation is identified in 1 of the other genes that increase risk for breast, ovarian and other cancers, then a tailored surveillance plan should be developed based on the pattern of cancers associated with the specific genes and family history of cancer.  It is very important that this plan be developed by a team of health care professionals who have expertise in clinical cancer genetics, such as genetic counselors.

However, women under the age of 60 with “triple-negative” breast cancer, meaning estrogen receptor, progesterone receptor, and HER2 negative, are at risk of having a BRCA1 mutation, regardless of family history.

Testing for mutations in the BRCA1 or BRCA2 genes may not be beneficial for the average woman.  

What are the estimated cancer risks associated with HBOC?

Cancer risks for women with HBOC

  • Lifetime risk of breast cancer             50% to 85%

  • Risk of breast cancer before age 50    30% to 50%

  • Lifetime risk of ovarian cancer

    • BRCA1 gene mutation                        25% to 50%

    • BRCA2 gene mutation                        15% to 30%

  • Developing a second breast cancer    40% to 60%  (the risk of breast cancer occurring in the other breast rises approximately 2% to 3% per year)

Cancer risks for men with HBOC

  • Lifetime risk of breast cancer

    • BRCA1 gene mutation                        1% to 2% (10-fold increase over the general population)

    • BRCA2 gene mutation                        6%

  • Risk of prostate cancer

    • BRCA1 gene mutation                        some increased risk

    • BRCA2 gene mutation                        20%

  • Men with a BRCA2 gene mutation have a significantly increased risk of developing more aggressive prostate cancer before age 65 and therefore screening should begin at age 40.

Breast cancer subtypes and inherited mutations

Cancers diagnosed in people with BRCA mutations often have specific characteristics:

  • 60% to 80% of the breast cancers in women with a BRCA1 mutation are “triple negative,” as discussed above,

  • 70% to 80% of the breast cancers in women with a BRCA2 mutation are estrogen receptor-positive, progesterone receptor-positive, and HER2/neu-negative.

Other cancer risks for people with HBOC

Both men and women with mutations in the BRCA2 gene may be at an increased risk of other types of cancer, including melanoma and pancreatic, stomach, esophageal, and bile duct cancers. Mutations in other genes may be associated with an increased risk of developing breast and other cancers, including the Li-Fraumeni syndrome (TP53 gene), Cowden syndrome (PTEN gene), and others. The pattern of cancers in the family is often a clue to the specific gene that may explain the hereditary cancer for that family. Recently, new panels of multiple genes have been developed for testing in a patient with a strong personal and family history. Multigene panel tests include BRCA1 and BRCA2 and many other genes that increase the risk of breast, ovarian and other cancers. If an individual has a negative test result for BRCA1 and BRCA2, then mutations in other genes may or may not be present. New testing technology -- sometimes referred to as “next generation sequencing,” “massively parallel sequencing,” or “deep sequencing” -- has made it faster and less expensive to test for mutations in multiple genes at the same time. If a genetic mutation is found, this could explain the cancers in a specific family and provide information about which family members are at risk and what type of monitoring and prevention/risk reduction methods are appropriate.

Risk reduction - What can I do to reduce my risk of developing cancer of the breast or ovary if I have a BRCA gene mutation?

Risk-reducing surgery

A prophylactic, bilateral mastectomy, which is the removal of both breasts, can reduce the risk of breast cancer by more than 90%. Only about 3% of breast cancers associated with BRCA mutations are diagnosed before age 30, so surgery could be considered over the age of 30 for most women.  However, bilateral mastectomy is an invasive and irreversible procedure.

A prophylactic salpingo-oophorectomy, which is the removal of the ovaries and fallopian tubes, can reduce the risk of ovarian cancer by approximately 90%. If this surgery is completed in premenopausal women, it is also associated with a 50% decrease in breast cancer risk. A special procedure to look for microscopic cancer in the ovaries and fallopian tubes is recommended following this procedure.

Deciding whether or not to have such surgery to reduce your risk of developing breast or ovarian cancer is a very personal decision. Your doctor and genetic counselor can help you understand the risks and benefits, based on your health, BRCA mutation status, and family history of cancer.

Chemoprevention

Cancer chemoprevention is the use of drugs to stop or keep cancer from developing. Tamoxifen (Nolvadex, Soltamox) taken for 5 years by women at high risk reduces the risk of breast cancer by 50%, as proven by multiple large, randomized clinical trials. Observational studies suggest a reduction in the risk of developing breast cancer among women with BRCA1 and BRCA2 mutations (although there is some question about its effectiveness in BRCA1 mutation carriers given their tendency to develop hormone receptor-negative cancers). Risk-reducing tamoxifen is a reasonable option for women with BRCA1 or BRCA2 mutations to consider in addition to screening.  Raloxifene (Evista) and aromatase inhibitors (ALs) are also effective for breast cancer prevention in high-risk women, and thus can be considered as an alternative to tamoxifen; however, data on their effectiveness in women with BRCA1 or BRCA2 mutations are lacking. 

Oral contraceptives (birth control pills) taken for 5 years by individuals with BRCA1 or BRCA2 mutations may be associated with a decreased risk of ovarian cancer by approximately 50%. This must be balanced by a potential slight increase in the risk of breast cancer.

Screening - What are the screening options for HBOC?

It is important to talk with your doctor about the following screening options, as each individual is different:

Screening for women with a BRCA1 or BRCA2 gene mutation

  • Monthly breast self-examinations, beginning at age 18

  • Clinical breast examinations performed twice a year by a doctor or nurse, beginning between the ages of 25 to 30

  • Yearly magnetic resonance imaging (MRI) scans of both breasts, beginning at age 25

  • Yearly MRI alternating every 6 months with mammograms, beginning at age 30

  • Pelvic examination, trans-vaginal ultrasound with color doppler, and CA-125 blood test every 6 months, beginning at age 30.  It should be noted, however, that screening for ovarian cancer is not yet able to identify the majority of early cancers.

  • Consideration of prophylactic salpingo-oophorectomy, by age 40 or once child-bearing is complete.

Screening for men

  • Monthly breast self-examinations, beginning around age 30

  • Yearly clinical breast examinations, beginning around age 30

  • Consider a baseline mammogram at age 35 for men with a BRCA2 gene mutation, if there is gynecomastia, meaning swelling of the breast tissue in boys or men, or if enough breast tissue is present for mammogram

  • Yearly prostate cancer screening with digital rectal exam and PSA blood test, beginning at age 40. Current U.S. Preventive Services Task Force (USPSTF) guidelines for men that recommend reducing the use of PSA screening do not apply to men with a BRCA1 or BRCA2 gene mutation.

Screening options may change over time as new technologies are developed and more is learned about HBOC. It is important to talk with your doctor about appropriate screening tests for you.

Learn more about what to expect when having common tests, procedures, and scans.

Questions to ask the doctor

If you are concerned about your risk of breast cancer or ovarian cancer, talk with your doctor. Consider asking the following questions of your doctor:

  • What is my risk of developing breast and ovarian cancers?

  • What can I do to reduce my risk of cancer?

  • What are my options for cancer screening?

If you are concerned about your family history and think your family may have HBOC, consider asking the following questions:

  • Does my family history increase my risk of breast cancer or ovarian cancer?

  • Should I meet with a genetic counselor?

  • Should I consider genetic testing?

More Information

The Genetics of Cancer

Genetic Testing

What to Expect When You Meet With a Genetic Counselor

Collecting Your Family Cancer History

Sharing Genetic Test Results with Your Family

Additional Resources

National Comprehensive Cancer Network - Guidelines for Patients
www.nccn.org/professionals/physician_gls/PDF/genetics_screening.pdf

Facing Our Risk of Cancer Empowered (FORCE)
www.facingourrisk.org  

Young Survival Coalition
www.youngsurvival.org

National Ovarian Cancer Coalition
www.ovarian.org  

Foundation for Women’s Cancers
http://www.foundationforwomenscancer.org/

National Cancer Institute
www.cancer.gov

To find a genetic counselor in your area, ask your doctor or visit the following websites:

National Society of Genetic Counselors
www.nsgc.org

National Cancer Institute: Cancer Genetics Services Directory
www.cancer.gov/cancertopics/genetics/directory