Annual breast cancer screening that includes magnetic resonance imaging (MRI) reduces the frequency of advanced breast cancers among women with a BRCA1 or BRCA2 mutation. These results were published in the Journal of Clinical Oncology.
Inherited mutations in two genes—BRCA1 and BRCA2—have been found to greatly increase the lifetime risk of developing breast and ovarian cancer. Mutations in these genes can be passed down through either the mother’s or the father’s side of the family.
Options to manage this increased cancer risk include regular cancer screening, chemoprevention (use of medications to reduce risk), or preventive surgery (surgery to remove the breasts and/or ovaries before cancer is diagnosed).
For women at high risk of breast cancer, the American Cancer Society recommends that breast cancer screening include magnetic resonance imaging (MRI) as well as mammography. MRI uses radio waves and a magnet to create detailed images of the inside of the body. For the detection of breast cancer, MRI tends to be more sensitive than mammography.
To explore whether the addition of MRI to mammography results in the detection of earlier-stage breast cancers, researchers conducted a study among 1,275 women with a BRCA1 or BRCA2 mutation.
Four hundred forty-five of the women were assigned to annual screening with MRI, mammography, and clinical breast exam. The remaining women—who were participants in another study of BRCA1/2 mutations—served as the comparison group. A screening protocol was not formally specified for women in the comparison group, but screening tended to consist of annual mammography and breast exam.
- The overall frequency of breast cancer was similar in the two study groups.
- Women in the MRI group had a higher occurrence of early-stage cancers and a lower occurrence of later-stage cancers than women in the comparison group. At six years, rates of DCIS or Stage I breast cancer were 13.8% among women in the MRI group and 7.2% among women in the comparison group. Rates of Stage II-Stage IV cancer were 1.9% among women in the MRI group and 6.6% among women in the comparison group.
These results suggest that among women with a BRCA1 or BRCA2 mutation, the addition of MRI to mammography and clinical breast exam reduces the likelihood that a woman will be diagnosed with more advanced breast cancer.
The researchers note that it will be necessary to continue to follow study participants in order to confirm that the reduction in advanced cancers ultimately leads to a reduction in breast cancer mortality.
Reference: Warner E, Hill K, Causer P et al. Prospective study of breast cancer incidence in women with a BRCA1 or BRCA2 mutation under surveillance with and without magnetic resonance imaging. Journal of Clinical Oncology. Early online publication March 28, 2011.