A large study found that in women with an abnormal BRCA1 gene, annual screening using BOTH a mammogram and a breast MRI (magnetic resonance imaging) was better at diagnosing breast cancer earlier than annual screening with only one of these tests. Women with an abnormal BRCA1 gene have up to an 85% risk of developing breast cancer over their lifetimes.
The women in this study who had both tests every year were found to live about 1.5 years longer than women who had only one test per year. This survival difference is most likely because the women who had both screening tests were diagnosed with breast cancer at an earlier stage, when it's most treatable. The breast cancers diagnosed using both screening tests were smaller (about 1.1 centimeters) than cancers diagnosed using only 1 test (about 1.3 to 1.9 centimeters).
Mammograms and MRI create images of the breast in different ways. Each test can be better at finding different forms and stages of breast cancer. Using both tests can make it more likely to find breast cancer sooner. This study adds to evidence that suggests MRI alone may be better than mammogram alone for routine screening using only one test. Still, MRI cost and availability make routine screening with MRI impractical for women with average breast cancer risk. Annual mammograms are a good and effective screening method for most women older than 40.
One side effect of using both screening tests each year is more breast cancer "false alarms" -- a strong suspicion of breast cancer when there is no breast cancer. When there's a strong suspicion of breast cancer, doctors usually recommend a breast biopsy. One out of every 3 women in this study had a breast biopsy done when there was no breast cancer. In addition to the discomfort, inconvenience, and expense of extra procedures such as a biopsy, women who have false alarms are understandably anxious and fearful until they get the results back saying they don't have cancer. For women at very high risk for breast cancer, the benefits of aggressive screening (annual mammogram AND MRI) may outweigh the inconvenience of any false alarms. For women who have average breast cancer risk, an annual mammogram with no MRI usually makes the most sense.
If you have an abnormal breast cancer gene or are at high risk for breast cancer because of your personal or family medical history, talk to your doctor about a screening plan that is best for you. This might include getting both mammograms and breast MRIs each year, as well as more frequent screening. You also might want to talk to your doctor about all your options (diet, lifestyle, and exercise choices as well as medical and surgical choices) for keeping your breast cancer risk as low as it can be.