Breast cancer patients, many of whom are mothers, wonder what the disease will mean for their daughters and other family members. My patients are often concerned that they passed on “the breast cancer gene” to their children. I’d like to help you understand how genetics affect breast cancer so you and your family can find answers and stay healthy.
WHAT IS THE BREAST CANCER GENE?
The BRCA1 and BRCA2 genes, when functioning normally, produce proteins that suppress tumor production, so they actually protect you from getting certain types of cancer. It is mutations (changes) in these genes that increase your risk of getting certain types of cancer—most commonly breast and ovarian cancers. These dangerous mutations can be inherited, but only 5 – 10% of women with breast cancer have these mutated BRCA genes.
WHO SHOULD BE TESTED FOR BRCA MUTATIONS?
Mutations like the BRCA1 and BRCA2 are very uncommon. It is estimated that only 1 in 400 or 1 in 800 women in the general public have one of these significant BRCA mutations. Studies have found there are risk factors that can increase the chances of having a BRCA mutation. However, even people with these risk factors only have a 15 – 20% chance of having a BRCA mutation. People with these risk factors can be tested to see if they have a mutation. Many insurance companies will cover the cost of these tests, which are considered to be preventative care for high-risk patients.
RISK FACTORS FOR BRCA GENE TESTING
• A first or second-degree relative who was diagnosed with breast cancer before the age of 50. Any male first or second-degree relative diagnosed with breast cancer.
• 2 or more breast cancers in the same first or second-degree relative. 2 or more relatives on the same side of the family with breast cancer.
• Breast cancer and ovarian cancer in the same first or second-degree relative or in family members on the same side of the family. A family member diagnosed with triple-negative breast cancer before age 60.
• A first or second-degree relative with a known mutation of BRCA.
HOW DO I GET TESTED?
Genetic testing can be ordered by a physician or through a genetic counselor. It is often better to have the family member with breast or ovarian cancer tested first, since they are more likely to have the BRCA mutation. If they don’t have the BRCA mutation, they could not pass it on to anyone else. Keep in mind that these tests are complicated and don’t always give simple answers. Everyone’s genes are a little different, so there could be variances that you won’t understand. Your test results could show a variation from normal that may still be “normal.” This is why it is important to speak with a physician or genetic counselor prior to and while reviewing genetic test results. He or she can help you pick the right test based on your family history and explain the results to you.
WHAT IF I DO HAVE A HARMFUL MUTATION?
First, know that this does not mean you will get cancer. While your risk of developing cancer with one of these mutations is higher than that of the general population, it is not 100 percent. The table below lists the risk for developing breast or ovarian cancer, and this information changes as data continues to come in. There are ways to decrease risks for getting cancer, and close monitoring that can be done to catch cancers in early stages. The care options you choose are incredibly personal. Recently, I counseled a 17-year-old girl about the BRCA gene mutation and what that meant for her. That was a very different discussion from the one I had with a 60-year-old grandmother who had taken the test to get information to help her children. Prevention strategies come from a spectrum of options that include frequent exams, MRIs and medications. It may even be necessary to remove breast tissue and ovaries with surgery, which can nearly eliminate the risk of breast and ovarian cancer. It is important to review your options with a physician so you can make an informed decision that is right for you.
RISK OF DEVELOPING CANCER BY THE AGE OF 70
BRCA1 —Breast Cancer:55 - 65%
BRCA1 —Ovarian Cancer: 39%
BRCA2 —Breast Cancer: 45%
BRCA2 —Ovarian Cancer: 15%
IF I DON’T HAVE THE BRCA MUTATION, DOES THAT MEAN I CAN’T GET BREAST CANCER?
Unfortunately, no. 90 – 95% of women with breast cancer and 85% of women with ovarian cancer do not have mutations in their BRCA genes. The lifetime risk for the general population to develop breast cancer is about 12%, and the risk for developing ovarian cancer is 1.3%. However, there are things you can do that have been shown to decrease the risk of breast cancer.
ACTIVITIES AND CONDITIONS:
MODERATE EXERCISE Decreases by 15 – 25%
ESTROGEN / PROGESTERONE HORMONE REPLACEMENT THERAPIES: Increase risk of breast cancer by 25%
DRINKING ALCOHOL: More than 3 or 4 alcoholic drinks per week INCREASES risk of breast cancer by 15%
BREASTFEEDING: DECREASES risk of breast cancer
TOBACCO USE: INCREASES risk of breast cancer OBESITY: INCREASES risk of breast cancer
RADIATION: INCREASES risk of breast cancer
KNOWLEDGE IS POWER
Breast cancer can be intimidating, but I hope this discussion has eased your mind. Don’t be afraid to ask your doctor any questions. Understanding BRCA mutations, diagnostic tests and cancer prevention measures will help you and your family stay well and happy.