What are hereditary breast and ovarian cancers?
Hereditary breast or ovarian cancer is breast or ovarian cancer that is linked to an inherited gene mutation. Only about 5 to 10% of breast and ovarian cancer cases are linked to an inherited genetic mutation. This means that most cases of breast and ovarian cancer are not caused by inherited genetic mutations.
If someone is found to carry a gene mutation, he or she inherited this mutation from his or her mother or father. In families in which a genetic mutation is passed down, multiple family members may get the same type(s) of cancer.
If a person inherits a mutation in either the BRCA1 or the BRCA2 gene (BRCA1/BRCA2), he or she is at risk for hereditary breast and ovarian cancer. There are mutations in genes other than BRCA1/BRCA2 that can cause breast or ovarian cancer to run in a family. We have not yet found all of these genes.Back to top
Are BRCA1/BRCA2 gene mutations more common in certain people?
Mutations in the BRCA1/BRCA2 genes are more common in some groups of people, including Jewish people whose ancestors lived in Central or Eastern Europe (Ashkenazi Jews). About 1 in 40 people of Ashkenazi Jewish ancestry carries one of 3 common BRCA1/BRCA2 mutations.Back to top
What does a negative BRCA1/BRCA2 test result mean?
A negative test result means that no BRCA1/BRCA2 mutation was found. This can happen if:
- You have a mutation in the BRCA1 or BRCA2 gene that cannot be detected with the method that was used. No one gene testing method can find all mutations in a gene.
- You have a mutation in a different gene. For example, even if you tested negative for BRCA1/BRCA2 mutations, your genetic counselor may recommend testing for mutations in a different gene that could cause breast or ovarian cancer. Testing for rare mutations or for panels of multiple cancer predisposition genes is available and may be covered by insurance in some cases. We suggest you talk with your genetic counselor about this. In addition, more genes will probably be discovered in the future.
- Your personal or family history of cancer happened by chance. For instance, breast cancer is a common cancer. It can develop in several people in the same family without being caused by a genetic mutation.
- There is a genetic mutation in your family, but you did not inherit it.
What does a positive BRCA1 test result mean?
Females with BRCA1 mutations are at increased risk for breast and ovarian cancers (or fallopian tube and peritoneum cancers, which are related to ovarian cancer). However, these risks may vary from family to family. Females with a BRCA1 mutation have a 50% to 85% risk of developing breast cancer by age 70. The risk of developing ovarian cancer is 40% to 60% by age 85.
A female with a BRCA1 mutation who has cancer in one breast has a higher risk of developing cancer in the other breast. For instance, 25% to 30% of females with breast cancer and a BRCA1 mutation may get a second breast cancer in the 10 years after their first breast cancers.
Both males and females with BRCA1 mutations have an increased risk for certain other cancers, including prostate cancer (in men) and pancreas cancer.
What does a positive BRCA2 test result mean?
Both males and females with BRCA2 mutations are at increased risk for breast cancer. In females who carry BRCA2 mutations, the risk for breast cancer is slightly lower than that for those with BRCA1 mutations. The risk for ovarian cancer is also less than that of a BRCA1 mutation. The risk for ovarian cancer due to a BRCA2 mutation is 16% to 27% by age 85.
Males with BRCA2 mutations have increased risks for breast and prostate cancers.
The risks of pancreatic cancer and melanoma are also increased in those with BRCA2 mutations. The risk of pancreatic cancer is about 3% to 5% by age 70. The risk of melanoma is not clearly known.
Individuals with BRCA1 or BRCA2 mutations may get one or more of the cancers mentioned, or none at all.Back to top
What does a “variant of uncertain significance” (or “ambiguous”) test result mean?
Genes are written in chemical bases almost like the letters of a sentence. A wrong spelling of a gene can cause an increased risk of cancer. However, changes in the spelling of a gene may differ in people without cancer. We are still learning which spellings are normal (harmless) and which can cause an increased risk for disease. These kinds of uncertain changes are called “variants of uncertain significance.”
If you have a variant of uncertain significance in the BRCA1 or BRCA2 gene, we may not be able to tell you whether you are at increased risk for cancer. We will make cancer screening recommendations for you based on your family history. We may suggest testing certain relatives to learn more about the variant, but this information will probably not be helpful in predicting cancer risks for your relatives. Future research may make it clearer whether a variant of uncertain significance leads to increased risks of cancer.Back to top
How should females with BRCA1/BRCA2 mutations manage their risks of cancer?
A female with a BRCA1/BRCA2 mutation has several options to manage her risk of cancer. She can choose to undergo additional breast screening that is not usually available to females at population risk, to try to detect cancer at an early stage if it develops. This screening includes:
- Yearly mammograms beginning at age 25. Researchers are looking at ways of improving mammograms, like contrast-enhanced screening mammography
- Magnetic resonance imaging (MRI) of the breast beginning at age 25
- Breast exams by a physician every 6 months
- Ultrasound of the breast (in certain situations)
It is important to realize that screening does not prevent cancer. Current tests cannot always find cancers when they are small enough to be treated successfully.
Females with BRCA1/BRCA2 mutations may choose to undergo surgery to try to prevent cancer. Surgery to reduce the risk of breast cancer is called prophylactic or preventive mastectomy. During this surgery, as much breast tissue as possible is removed. Since not all breast tissue can always be removed, prophylactic mastectomy may not be 100% effective at preventing cancer.
Screening for ovarian, fallopian tube or peritoneum cancer has not been proven to be helpful. To decrease the risk of ovarian cancer, we recommend removal of both ovaries and both fallopian tubes. This surgery is called a salpingo-oophorectomy (sal-pin-gō ō-fa-rek-ta-mē). Removing the ovaries and fallopian tubes before age 50 also reduces the risk of breast cancer. In rare cases, a cancer of the peritoneum (the lining of the abdomen) can occur after surgery because the peritoneum is made up of similar tissue as the ovaries, but cannot be removed surgically. There is no proven way to screen for cancer of the peritoneum.
Females who choose not to remove their ovaries and fallopian tubes may instead consider having ultrasound of the ovaries twice a year with a pelvic exam and a blood test called CA125. The best age to begin ultrasound screening is not clear, but we suggest starting by age 30 to 35 for women with a BRCA1 mutation. In those with a BRCA2 mutation, the screening should start by age 35 to 40. It should be noted that ovarian cancer screening has not been shown to reduce ovarian cancer mortality in any group, and females at risk should discuss risk-reducing surgery with their physicians once child-bearing is complete.
Some medications may decrease the risk of breast or ovarian cancers. For example, tamoxifen and raloxifene (Evista®) may lower breast cancer risk. However, it is not clear whether these medications reduce breast cancer risk in females with BRCA1/BRCA2 mutations. Oral contraceptives (OCs) may reduce the risk of ovarian cancer. However, some studies have suggested that OCs may slightly increase the risk of breast cancer in females with BRCA1/BRCA2 mutations.
Females with BRCA1/BRCA2 mutations should continue to follow the other recommendations for cancer screening that are appropriate for people without mutations. For example, they should have Pap smears to screen for cervical cancer and colonoscopies to screen for colon cancer.Back to top
How should males with BRCA1/BRCA2 mutations manage the risk of cancer?
Males with BRCA1/BRCA2 mutations should be screened for prostate cancer. The best age to start screening is not yet clear, but we recommend starting by age 40. Screening consists of a yearly physical exam and a blood test called PSA. Prostate cancers do not seem to develop early in males with BRCA mutations.
Males with BRCA1/BRCA2 mutations have increased risks for breast cancer. We recommend regular clinical breast exams and a yearly mammogram, if possible. Any breast changes should be evaluated quickly.
Males with BRCA1/BRCA2 mutations should continue to follow the other recommendations for cancer screening that are appropriate for people without mutations. For example, they should have colonoscopies or other screens for colon cancer.Back to top
If I have a BRCA1/BRCA2 mutation, what are the risks to my children?
If you carry a BRCA1/BRCA2 mutation, each of your children (or future children) has a 50% (1 in 2) chance of inheriting that mutation. A child who inherits the mutation will also inherit the associated cancer risks. It is important to remember that just inheriting the mutation does not automatically mean that a person will develop cancer.
Some people with mutations want to know when their children should be tested. The screening for females with BRCA1/BRCA2 mutations typically begins in their mid-20s, and even later for males. Therefore, we do not recommend testing until the mid-20s.Back to top
If I have a BRCA1/2 mutation, what are my options for having children?
If a BRCA1/BRCA2 mutation is identified in your family, you may want to learn about family planning options (starting a family or having more children). For example, embryos can be tested for the family’s genetic mutation before they are even implanted in a woman’s uterus. This process is called preimplantation genetic diagnosis (PGD). PGD is performed with in vitro fertilization, and may be an option for families who wish to have children without the hereditary cancer risk. To learn more, ask for a referral to a specialist before attempting pregnancy.
Having children with the assistance of donor eggs or donor sperm and adoption are other possible family planning options.Back to top
Who should I contact if I have questions?
If you have any questions or concerns, please contact MSK’s Clinical Genetics Service at 646-888-4050.Back to top