Genetic testing for cancer in the national spotlight
The topic of genetic testing for breast cancer has been in the national spotlight this week as the world learned that actress Angelina Jolie underwent a bilateral mastectomy to lower her risk of developing breast cancer.
The actress made the stunning announcement that has brought attention to use of genetic testing to determine predisposition to cancer and the BRCA1 gene.
According to Susie Caro, advanced practice nurse in genetics and director of the Saint Thomas Health Family Cancer Risk Services, BRCA1 and BRCA 2 act as tumor suppressor genes and are associated with hereditary susceptibility to breast, ovarian, and other cancers.
Women who carry mutations in BRCA1 or BRCA2 may face a breast cancer risk of nearly 60 percent to age 70, compared with the general population risk of around 7 percent up to age 70. The earliest studies of very high risk families found cancer risks of up to 87 percent up to age 70 for mutation carriers. Ovarian cancer risk is also significantly increased in women who carry mutations in BRCA1 or BRCA2, with risks of 40-60 percent compared with less than 2 percent for the general population. Genetic testing is clinically available for BRCA1 and BRCA2. It is recommended that individuals seek consultation with a cancer genetics specialist before pursuing testing.
“Family history is one of the most significant factors for many cancer types in identifying those who may be at increased risk,” Caro said. “Our challenge as clinicians is to clarify risks for individuals and families so that appropriate surveillance and screening or risk-reducing measures can be offered to those at significantly increased risk of developing specific cancers.”
The explosion of information concerning hereditary cancers that has come in the aftermath of the Human Genome Project has allowed for characterization of hereditary cancer syndromes. Understanding of these syndromes and the clinical availability of genetic tests for diagnosis provides incredible opportunities to identify cancers earlier, to lower the risks of cancer, or even prevent cancers or cancer deaths by identifying those individuals who may be at very high risk.
Genetic testing also allows for the identification of those who may not be at grave risk, and therefore can be spared increased surveillance or risk-reducing surgeries.
Between 5 and 10 percent of many cancers may be due to inheritance of a single genetic mutation associated with a recognized hereditary cancer syndrome. The most well-known of these is BRCA1 and BRCA2. Breast cancer is part of several other hereditary cancer syndromes as well.
If you are concerned about the chance of hereditary cancers, a cancer risk assessment can be performed and includes a review of personal medical history and family history, review of medical records, and use of risk assessment models to help clarify risks. Genetic testing is done when appropriate after careful discussion of the potential benefits and limitations of the testing. In most instances, testing is covered by insurance. The laboratories that provide these tests will check insurance coverage prior to proceeding with the testing.
If you have questions about the implications of a cancer diagnosis on your family or your risks of additional cancers, visit or call the Saint Thomas Health Family Cancer Risk Services at www.familycancerriskservices.com or 615-284-2276, or discuss your options with your health care providers.