When I meet new people and introduce myself as a genetic counselor, I often get blank stares or funny jokes about making designer babies (no, I don’t do that!). I think of myself as an educator, a translator and a support person for families with a hereditary disease. A genetic counselor helps families take a closer look at their family tree, determine if genetic testing is right for them and interpret the often complex results so that they can take proactive steps in their healthcare. At Texas Oncology, our team of genetics experts provides genetic evaluations and testing to identify families that are at high risk for cancer so we can detect cancers early and prevent future cancers from occurring. While testing for hereditary cancer syndromes has been available for many years now, awareness of the BRCA or breast cancer genes, increased in 2013 when actress Angelina Jolie announced that she is a BRCA1 mutation carrier. Most people have now heard of the BRCA genes, but I often get questions about cancer genetic testing and the BRCA genes. Here are some of the most common questions:
Cancer can be inherited?
Did you know all cancer is genetic but that only some cancer is hereditary, or inherited? Cancer is caused by changes, or mutations, in genes that control the way our genes work, especially in genes that control how cells grow and divide. As we live our lives, we can acquire mutations in our DNA, most of which occur by chance or due to environmental exposures. If a gene that is responsible for cell growth acquires a mutation, then that gene no longer works and cells will grow uncontrollably. This is cancer. The majority of cancer just happens by chance but, about 5-10% of all people are actually born with a mutation in an important gene that can lead to an increased risk for cancer.
What are the BRCA Genes?
The BRCA genes are tumor suppressor genes. Their job is to prevent uncontrolled cell growth and abnormal cells from turning into cancer. Every person has two copies of the BRCA1 gene and two copies of the BRCA2 gene, and most people have functioning copies. A person with a mutation in a BRCA gene is often called a BRCA carrier. Individuals with BRCA mutations have higher lifetime risks for cancer than other people because the gene can’t do its job.
How many people have a BRCA mutation?
It is important to remember that everyone has the BRCA genes, but it is rare to have a mutation in a BRCA gene. About one in 400 people have a mutation in a BRCA gene. BRCA mutations are more common in individuals of Ashkenazi Jewish Ancestry, where about one in 40 people have a mutation. It is estimated that close to one million people in the United States have a BRCA mutation, but less than 10% are aware that they have a mutation that increases their risk for cancer.
What types of Cancer do the BRCA Mutations Cause?
The BRCA genes have long been known as the breast cancer genes, but we now know that these genes can cause a variety of types of cancer. The risk for breast cancer in a woman with a BRCA mutation is about 66-67%. This is much higher than the risk for breast cancer in women without a BRCA mutation, which is about 12%. We also know that women with BRCA mutations who have had one breast cancer are at significantly higher risk for a second breast cancer. The risk for ovarian cancer is also increased between 12-45% over a lifetime. We also know that the risks for male breast cancer, prostate cancer, pancreatic cancer and melanoma are increased for individuals with a mutation in BRCA1 or BRCA2. It’s important to remember that men carry BRCA mutations as well and are at increased risk for cancer!
What do you do differently if you have a BRCA mutation?
When Angelina Jolie announced that she has a BRCA mutation, she also shared her decision to have a risk reducing mastectomy. I often get asked if this is the only option for BRCA carriers. Fortunately, the answer is no. We now have many options to discuss with BRCA mutation carriers, including increased surveillance for cancer, medications to reduce risk, and risk reducing surgery.
Surveillance: Increased breast cancer screening for women with a BRCA mutation includes monthly self-breast exams, clinical breast exams with their doctor twice a year, annual mammograms, and annual breast MRIs. Currently, there are no known effective screening techniques for ovarian cancer. Men with BRCA mutations should have clinical breast exams and prostate cancer screening.
Risk Reducing Medicines: Chemoprevention, or medications that reduce cancer risk, can also be considered. There are medications such as tamoxifen that are known to reduce the risk for breast cancer. Also, oral contraceptives are known to reduce the risk for ovarian cancer. A discussion of the risks and benefits of these types of medications is important for women who are considering these medications.
Surgery: Women with BRCA mutations can consider having a bilateral mastectomy, or removal of both breasts, with or without reconstruction, to reduce breast cancer risk. Given that the risk for a first and SECOND breast cancer is higher in BRCA carriers, this is an option that significantly reduces the risk for breast cancer. This is a major surgery, and BRCA carriers should have a discussion with their healthcare provider to decide if this is the right procedure for them.
Since there currently are no effective screening tests for ovarian cancer, women with BRCA mutations are recommended to have their ovaries and fallopian tubes removed, to reduce their risk of ovarian cancer. This is called a bilateral salpingo-oophorectomy. Typically, a salpingo-oophorectomy is recommended after completion of childbearing (usually around age 35-40). Not only does this procedure reduce the risk for ovarian cancer, but it also reduces the risk for breast cancer and has been associated with a 77% reduction in overall risk of death.
BRCA carriers have many difficult decisions to make, but knowing your genetic status can help you feel empowered to make decisions to reduce risk and prevent cancer.
How does a BRCA mutation run in a family?
Mutations in the BRCA genes are typically inherited from a parent and are passed down from generation to generation. A person who has a BRCA mutation has a 50% chance of passing the mutation on to each of their children. These mutations do not skip generations but sometimes appear to, since not all people with BRCA mutations develop cancer. Both men and women can have BRCA mutations and can pass them onto their children.
I think I need testing, what should I do?
While there are many people with BRCA mutations, not everyone needs genetic testing. By reviewing your family history, a genetics professional can help you determine if you need genetic testing and the most appropriate test. Signs of hereditary breast and ovarian cancer or BRCA mutations are:
- Ovarian cancer at any age (this includes fallopian tube cancer and primary peritoneal cancer)
- Breast cancer at age 45 years or younger
- Two breast cancers in the same woman with one before the age of 50
- Two family members with breast cancer on the same side of the family, one with breast cancer before 50
- Male breast cancer
- Breast cancer at or before age 60 that is “Triple Negative,” or a ER, PR, HER2 negative breast cancer
- Three or more family members with breast cancer, ovarian cancer, and/or aggressive prostate cancer
- Ashkenazi Jewish Ancestry and a personal or family history of breast, ovarian, or pancreatic cancer
If you or your family has any of the above features, you should ask your doctor for a referral for a cancer genetic evaluation.
Click here to read the full story from Breast Cancer Resource Center.