Patient education: Genetic testing for breast and ovarian cancer (Beyond the Basics)
- Beth N Peshkin, MS, CGC
Beth N Peshkin, MS, CGC
- Professor of Oncology, Senior Genetic Counselor
- Georgetown University Medical School
- Jess and Mildred Fisher Center for Hereditary Cancer and Clinical Genomics Research
- Claudine Isaacs, MD
Claudine Isaacs, MD
- Professor of Medicine and Oncology
- Georgetown University Medical School
- Jess and Mildred Fisher Center for Hereditary Cancer and Clinical Genomics Research
- Section Editors
- Daniel F Hayes, MD
Daniel F Hayes, MD
- Section Editor — Breast Cancer
- Professor of Medicine
- University of Michigan School of Medicine
- Benjamin A Raby, MD, MPH
Benjamin A Raby, MD, MPH
- Section Editor — Genetics
- Associate Professor of Medicine
- Harvard Medical School
Having a personal or family history of breast or ovarian cancer can increase your risk of developing these cancers (or getting cancer again). A personal history means that you've had cancer yourself. A strong family history means that:
●Multiple family members have or had breast or ovarian cancer, often diagnosed before age 50, or
●A family member has or had both breast and ovarian cancer, or
●More than one generation of your family (for example, your mother and grandmother) has or had breast or ovarian cancer
However, having even one relative with early-onset breast cancer, male breast cancer, or ovarian cancer may be associated with hereditary breast/ovarian cancer. In addition, individuals with a personal or family history of breast or ovarian cancer who are Ashkenazi Jewish (descended from central or eastern Europe) also have an increased risk of hereditary breast/ovarian cancer due to alterations in specific genes known as BRCA1 and BRCA2.
Genetic testing can tell if you have inherited an abnormal gene that increases the risk of breast and ovarian cancer. Many women who are candidates for genetic testing are offered testing for alterations (mutations) in several genes associated with hereditary breast/ovarian cancer.
Genetic counseling is important before and after testing. A counselor can help answer your questions about the testing and understand what is involved. If you test positive for a gene alteration, there may be steps you can take to find cancer early or to decrease your risks. However, genetic testing is not perfect. Most women with breast cancer and/or a family history of breast cancer do not have an abnormal gene, and not all women who have inherited a gene alteration will develop cancer.
This article will discuss who should consider genetic testing, issues to consider before you have testing, and what you can do after testing to find cancer early or to reduce your risk. More detailed information about genetic testing is available by subscription. (See "Genetic counseling and testing for hereditary breast and ovarian cancer".)
WHAT IS GENETIC TESTING?
Cancer develops because of mutations in one or more genes. Genes hold information about how you look and how your body works, and genes are passed from parents to children. If there is an abnormality in a gene, this is called a genetic mutation.
There are two types of genetic mutations:
●Germline mutations are inherited, passed from parent to child. Between 5 and 10 percent of breast cancers are caused by germline mutations. Mutations in two major genes, known as BRCA1 and BRCA2, are a frequent cause of hereditary breast/ovarian cancer. These mutations increase the risk of developing these and other cancers.
Most genetic testing for breast and ovarian cancer analyzes these two genes for mutations. However, many women are offered what is called multi-gene or panel testing, which includes analysis of a number of genes associated with hereditary cancer. For example, panels may assess only those genes in which mutations are associated with very high risks of breast and/or ovarian cancer. Larger panels may also include more moderate-risk genes or newer genes, for which less information is known about cancer risks and management options. Genetic testing is done on a mouthwash sample (to obtain cells from inside the cheek) or a sample of blood.
●Acquired mutations are not inherited, but instead develop during your lifetime. Acquired mutations can be caused by exposure to environmental agents such as radiation, chemicals (including those found in tobacco smoke), or viruses; they can also develop without a known cause. Most cancers, including breast cancer, are caused by acquired mutations. Acquired mutations are found only in the tumor itself, whereas germline mutations are present in cells throughout the body.
WHO SHOULD CONSIDER GENETIC TESTING?
Genetic counseling and testing should be considered for women who have (or have had):
●A diagnosis of ovarian cancer at any age.
●A history of early onset breast cancer, meaning they were diagnosed at age 50 or younger, or age 60 or younger for "triple-negative" breast cancer (a type of breast cancer that lacks proteins on the surface of its cells called hormone receptors or HER2 receptors).
●A diagnosis of male breast cancer at any age.
●Multiple close family members affected with breast or ovarian cancer, particularly if the relative was diagnosed with cancer at an early age (less than 50 years old). Close family members include your mother, sister, or daughter; close family members can include men with breast cancer.
●A personal history or close family member with more than one cancer, such as breast cancer involving both breasts or breast and ovarian cancer.
●Multiple generations of close family with cancer (eg, grandmother, mother, sister). Family history on the father's side is as important as the mother's side. It is also important to know the cancer history of your cousins on both sides of your family.
●A personal or family history of cancers besides breast and ovarian cancer – This can be suggestive of hereditary cancer. For example, it is important to know if there are relatives with pancreatic, prostate, colon, or male breast cancer.
●A personal or family history of breast, ovarian, prostate, or pancreatic cancer and are of Ashkenazi Jewish descent (from central or Eastern Europe) – People in this situation may consider testing.
When indicated, BRCA testing should be initiated with an individual who has cancer rather than a family member without cancer, whenever possible. Usually this means testing a woman with ovarian cancer or breast cancer diagnosed at the youngest age within the family. If a mutation is not found, it is often not helpful to test family members without cancer.
Pretest counseling — Before you have genetic testing, it is important to consider the medical, emotional, practical, and financial effects of testing on you and your family. You should discuss these issues with a certified genetic counselor, if possible, to understand what is involved in genetic testing. A list of certified genetics counselors and their phone numbers is available through the National Cancer Institute (www.cancer.gov/cancertopics/genetics/directory).
Costs and insurance coverage — Genetic testing is offered by many different labs. The cost varies depending on the extent of testing that is performed. In the United States, most health insurance companies will cover most of the costs. However, insurance companies often have specific criteria that must be met to cover testing. Your doctor or genetic counselor might need to write a letter to explain why testing is needed.
Many people are worried about how the results of genetic testing will affect the chance of getting health or life insurance in the future. In the United States, a federal law known as the Genetic Information Nondiscrimination Act (GINA) prohibits health insurers and employers from using your genetic information. This law is intended to encourage Americans to take advantage of genetic testing if needed. In general, the law means that:
●Employers cannot deny you a job or fire you because of the results of genetic testing.
●Health insurers cannot use genetic testing results to deny you coverage or set your insurance rates.
●Employers and insurers cannot require you to have genetic testing.
The law does not have provisions for disability, life insurance, or long term care insurance. In addition, GINA does not apply to individuals in the military. State laws may provide additional coverage.
Posttest counseling — After genetic testing is done, it is important to understand what the results mean for you and your family. During this discussion you can find out how your test results affect your cancer risks and what options are available to you to find cancer early or reduce your risk. You can ask questions and obtain resources for more information and support.
If you test positive for a mutation in a gene such as BRCA1 or BRCA2, it is important that you talk with your family about the results. Some family members will want to talk to their doctor or nurse about having genetic testing.
INTERPRETING THE RESULTS
It is not always easy to interpret the results of genetic tests. The results may be:
●Positive for a BRCA1 or BRCA2 or other harmful mutation. This means that a mutation was identified that is known to be associated with increased risks for cancer.
●Negative, meaning that you do not have a BRCA or other gene mutation. This result does not rule out the possibility that you may have a hereditary risk for cancer. Not every mutation is detected by genetic testing. In addition, there are many unknown genetic mutations that have not yet been discovered.
●A "true" negative result means that a mutation present in one or more of your family members was ruled out in you. This result usually means that your cancer risks are about the same as other women in the general population.
●Positive for a genetic mutation with "unknown significance." This means that you have a genetic change, but it is not clear if it increases your risk of breast or ovarian cancer or if it may be a normal change in the gene.
A negative result does not mean that you will not develop cancer and a positive result does not mean that you will definitely develop cancer.
The following is information about BRCA results and management. For information about other genes associated with hereditary breast/ovarian cancer, talk with your genetic counselor or doctor.
If a woman tests positive for a BRCA mutation:
●The lifetime risk (to age 70) of breast cancer is between 55 and 70 percent for BRCA1 and 45 to 70 percent for BRCA2. This means that in a group of 100 women with BRCA1, between 45 and 70 of the women will develop breast cancer in their lifetime.
The lifetime risk of ovarian cancer is about 40 percent for BRCA1 and 15 percent for BRCA2.
Test result interpretation can be complex. Sometimes “negative” results are more difficult to interpret than “positive” results. It is important to discuss what test results mean with a genetic counselor and your doctor.
MANAGING THE RISK OF CANCER
If you test positive for a BRCA mutation, there are several ways to screen for cancer and to reduce your risk of developing cancer:
●Have more frequent screening for breast and ovarian cancer
●Have surgery to reduce your risk
●Take a medicine to reduce your risk
The best strategy might include a combination of these methods.
If you test negative for a BRCA mutation but have a strong family history of breast or ovarian cancer, talk to your doctor or nurse about ways to manage your risk of developing cancer. (See "Management of patients at high risk for breast and ovarian cancer".)
Breast cancer screening — Women who have inherited a BRCA mutation are usually advised to have more frequent screening for breast cancer. This includes:
●A breast exam, performed by your doctor or nurse, every 6 to 12 months beginning at age 25.
●A mammogram once per year, beginning at age 30 (or individualized based on family history).
●A breast MRI once per year, beginning at age 25 or individualized based on family history.
●Breast awareness, beginning at age 18, which involves paying attention to changes in the breasts and may include periodic and consistent breast self-exams.
Ovarian cancer screening — Women who have inherited a BRCA mutation have an increased risk of developing ovarian cancer. However, screening tests for ovarian cancer are not very accurate in detecting the disease. (See "Patient education: Ovarian cancer screening (Beyond the Basics)".)
However, ovarian cancer screening may be an option if you have a BRCA mutation. Screening includes a combination of a blood test (called "CA-125") and a pelvic ultrasound. Some experts recommend this combination of tests every 6 to 12 months, beginning at age 30 to 35. (See "Patient education: Ovarian cancer screening (Beyond the Basics)".)
Surgery — An alternative to frequent cancer screening is surgery to reduce the risk of developing cancer. This is called preventive surgery, and it can significantly decrease your risk of cancer and may help you to feel less anxious. Talk to your doctor about the potential risks and benefits of preventive surgery.
Mastectomy — Women who have both breasts removed (called prophylactic bilateral mastectomy) reduce their chance of developing breast cancer by at least 90 percent. Women with breast cancer may also choose to have one or both breasts removed to reduce their risk of developing a second breast cancer.
Removal of the ovaries — Having the ovaries and fallopian tubes removed (termed a prophylactic bilateral salpingo-oophorectomy, or BSO) has been shown to reduce the risk of ovarian and fallopian tube cancer by 80 to 90 percent and may reduce the risk of breast cancer by 50 to 60 percent (for premenopausal women). The benefits of this surgery are greatest in women who have surgery before menopause, particularly before age 40, after you finish having children. Women with a BRCA mutation are strongly recommended to have a BSO typically between ages 35 and 40 years and once they are done having children. (See "Risk-reducing bilateral salpingo-oophorectomy in women at high risk of epithelial ovarian and fallopian tubal cancer".)
Medicines to reduce the risk of cancer — There is some evidence that certain medications can reduce the risk of cancer in particular situations:
●A medicine called tamoxifen can in certain circumstances reduce the risk of developing a second breast cancer in women who have BRCA mutations (particularly in those whose original breast cancer is "hormone receptor-positive"). However, the degree of risk reduction is not clear for women without a personal history of breast cancer. (See "Patient education: Medications for the prevention of breast cancer (Beyond the Basics)".)
●Hormonal birth control (pill, skin patch, vaginal ring, shot, implant) can decrease the risk of ovarian cancer. Data suggest that this is also true for women with a BRCA mutation, although most data have been gathered in women who used birth control pills. However, it is possible that hormonal birth control may increase the risk of breast cancer, particularly in women who have a BRCA1 mutation and start birth control at a young age and before their first pregnancy. If you have a BRCA mutation, talk to your doctor or nurse about the risks and benefits of hormonal birth control.
WHERE TO GET MORE INFORMATION
Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Overview of hereditary breast and ovarian cancer syndromes
Genetic counseling and testing for hereditary breast and ovarian cancer
Management of patients at high risk for breast and ovarian cancer
The following organizations also provide reliable health information.
●National Cancer Institute
●American Society of Clinical Oncology
●Facing Our Risk of Cancer Empowered (FORCE)
All topics are updated as new information becomes available. Our peer review process typically takes one to six weeks depending on the issue.