Breast Cancer Screening and Prevention

More Than Mammograms: MRI for High-Risk Women

Physicians and women have long awaited a better early detection tool for breast cancer than mammograms. And a recent study suggests that a new option, magnetic resonance imaging (MRI), can be added to the screening arsenal, though it's only recommended to women at high genetic risk for breast cancer.

Breast cancer screening is a top concern for women who have an inherited abnormality in one of two genes, known as the BRCA1 and BRCA2 genes. Yet few studies have examined what screening approach is best for these high-risk women. BRCA1 and BRCA2 mutation carriers are identified though blood tests that are given to certain women with a strong family history of breast cancer. Women of Ashkenazi Jewish descent are at particular risk: The mutations occur in about 2.5 percent of these women, compared to 1 percent of the general population.

A study published in the September 15th issue of the Journal of the American Medical Association looked at the usefulness of MRI, mammograms, ultrasound and clinical breast exams, which are breast exams performed by a healthcare professional, in screening healthy women with the BRCA1 and BRCA2 gene mutations for breast cancer. The researchers found that MRI, in which magnets and radiowaves create an image of a body part, was a helpful addition to the surveillance programs for these women.

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.

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