Other risk factors for breast cancer include age, family history, use of hormone replacement therapy, radiation exposure, early onset of the menstrual period and late menopause. However, the JAMA study only examined women with one of the BRCA mutations. Breast cancers related to BRCA1 or 2 mutations make up about 5 percent of all breast cancers.
Below, study author Sandra Messner, MD, the medical coordinator of clinical breast services in preventive oncology at the Toronto Sunnybrook Regional Cancer Center, discusses the best screening options for these high-risk women to help make sure any breast cancer they develop is detected as early as possible.
What are the BRCA mutations?
There are two large genes that have been identified in all women called BRCA1 and BRCA2. They function, we think, as tumor-suppressor genes, so they keep cancers from developing. If they are abnormal or what we call mutated, then your risk of cancer is increased, and the risk of breast cancer and ovarian cancer particularly is affected. If a woman carries an abnormality in one of those two genes, she is thought to have up to an 85 percent lifetime risk of breast cancer. The average woman's lifetime risk of developing breast cancer is about 11 percent. The mutations also increase the risk of ovarian cancer, more so with BRCA1 than with BRCA2. The BRCA2 mutations may also increase risk of other cancers, such as melanoma and pancreatic cancer.