To commemorate the 20th anniversary of the discovery of the BRCA1 gene, Kenneth Offit, Chief of Memorial Sloan Kettering’s Clinical Genetics Service, revisited last year’s Q&A on BRCA testing and cancer risk. See our updates and information on the latest advances in genetic testing below.
Actress Angelina Jolie ignited a national dialogue on breast cancer risk and genetic testing in May 2013 with an op-ed in the New York Times, in which she described her choice to undergo a preventive double mastectomy after learning she carries a mutation in a gene called BRCA1.
Certain inherited gene mutations are associated with an increased risk of breast and ovarian cancer. BRCA1 was first discovered 20 years ago; BRCA2 followed later. BRCA1 and BRCA2 mutations both are more common among people of Eastern European (Ashkenazi) Jewish ancestry. Memorial Sloan Kettering cancer geneticist and medical oncologist Kenneth Offit led the research team that identified the most common mutation in BRCA2, observed in those of Ashkenazi heritage.
Today, testing is available for mutations in BRCA2, as well as in BRCA1 and in other genes that have been linked to an increased risk for breast and ovarian cancer. Women can use the results of such genetic tests to make informed decisions — such as whether to surgically remove the breasts (preventive mastectomy) or ovaries (preventive oophorectomy) — to reduce their cancer risk.
In an interview, Dr. Offit notes that there have been great strides in prevention and early detection of breast cancer since the BRCA1 and BRCA2 mutations were identified. He encourages women and their families to take these factors into consideration when weighing their options.
Who should undergo genetic testing for breast cancer?
It’s very important that women speak to their physicians if they have a personal history of breast cancer or close relatives who have had breast, ovarian, or prostate cancer, or some other types of cancer. Other strong risk factors include having had breast cancer at an early age (before age 50), having both breast and ovarian cancer, having a male relative with breast cancer, and being of Eastern European Jewish ancestry. In addition all women with a personal history of ovarian cancer — regardless of their family history — should have BRCA testing.
While a significant number of women with breast cancer have a family history of the disease, only a small number may be advised to get genetic testing. Only about 5 to 10 percent of women with breast cancer will have an inherited risk of the disease due to BRCA mutations or other mutations.
What is involved in getting tested?
Genetic testing is not just a blood test — it’s a process of genetic counseling that often involves the family. We like to see individuals with their sisters, their mothers, their significant others, both as a support and to enable women and their family members to make mutual decisions about screening and prevention.
Women meet with a genetic counselor to review all the options available should a test turn out to be positive, and also visit with a doctor to go over their family history of cancer and other risk factors in more detail. Only at that point is the actual test given (if a woman chooses to have it). Results take a few weeks to come back.
What kind of information does genetic testing provide to women and their families?
If a woman tests positive for a BRCA mutation, she is not only at increased risk for breast cancer but also at increased risk for ovarian cancer. In fact, while the BRCA test is named after breast cancer, it is the ovarian cancer risk that we pay close attention to because we don’t have a means to screen for ovarian cancer to find it early, when it’s potentially curable.
When we first started doing genetic testing, we were very concerned about the negative impact that results might have. But we have found that genetic testing is in fact a very empowering experience both for women and their families, as there are now proven means for prevention and detection of some of the associated cancers.
If a genetic test shows that a woman has an increased risk for breast or ovarian cancer, what are her options?
There are at least three options available upon testing positive for BRCA mutations. Surgery is one of them, and it’s the most effective means of breast cancer prevention. And while the surgical option for breast cancer is just that — an option — we strongly recommend surgical removal of the ovaries to reduce the risk of ovarian cancer for women who no longer expect to have children.
Doctors at Memorial Sloan Kettering and other hospitals now have a very powerful means of screening for cancerous changes in the breast with magnetic resonance imaging, or MRI, which is more precise than mammography in finding early breast cancers. While most women in the United States choose screening over surgery, this is a discussion that needs to be individualized.
In addition, we can offer preventive treatment with drugs such as tamoxifen that for some women can cut the risk of breast cancer in half.
Do you foresee any new advances in genetic testing for breast or ovarian cancer?
Up until now, we have only been able to tell a woman who tests positive for a BRCA mutation that her risk for developing cancer ranges from 40 to 90 percent. But over the last several years, researchers at Memorial Sloan Kettering and elsewhere have discovered that there are genetic variations that will allow us to more closely pinpoint this risk. We hope to make these more-precise testing options available to women as part of our continued research.
Another research study now open at Memorial Sloan Kettering involves testing for genes other than BRCA1 and BRCA2 in women with family histories of breast and/or ovarian cancer who have already tested negative for BRCA1 and BRCA2. In this study we offer a “panel” of tests for other genes (for example PALB2, CHEK2, etc.) that have more recently been discovered, and about which little is known regarding preventive care that is required. Individuals have the option in this study to get results only on genes they wish to learn about. As part of this research, there is no cost for the testing. Eventually, we anticipate that these “panel” tests will be more widely available and covered by insurance.
Finally, as part of longer-term research, we are also using next-generation DNA sequencing to discover new genes associated with hereditary risk for breast or ovarian cancer.
To make an appointment with our Clinical Genetics Service, call 646-888-4050.
To make an appointment with one of our breast cancer specialists, call 646-497-9064.