The current breast cancer screening guidelines from the American Cancer Society recommend that women at high risk for breast cancer (typically greater than a 20% lifetime risk) receive both a yearly mammogram and a yearly magnetic resonance imaging (MRI) scan starting around 25-30 years of age. Women at elevated risk for breast cancer are generally those with gene mutations that increase breast cancer risk or have a family history of breast cancer. While previous research has shown that MRI breast cancer screening can be more efficient and detect breast cancer earlier than mammograms , the impact of MRI breast cancer screening on breast cancer survival has been uncertain.
Recently published results from the Dutch MRISC Screening Study suggests that MRI breast cancer screening might improve breast cancer survival in women at high risk for breast cancer. In this study, 2,157 women were categorized based on their cumulative lifetime risk for breast cancer as  moderate risk based on family history (15-30% lifetime risk),  high risk based on family history (30-50% lifetime risk), and  BRCA1/2 gene mutation carriers (50-85% lifetime risk). All women in the study received annual screenings that consisted of a yearly mammogram, twice yearly clinical breast cancer exams, and a yearly breast MRI and were followed for about 5 years from study entry or breast cancer diagnosis. The breast cancer researchers reported that
MRI screenings were slightly more than twice as sensitive at detecting invasive breast cancer than mammograms.
No differences between MRI and mammograms were evident in the detection of ductal carcinoma in situ.
The ability to detect invasive breast cancers with mammograms was lower in women with the BRCA1 gene mutation (25%) compared to women in the BRCA2 group (~62%) and women with a family history of breast cancer (~45-47%).
The proportion of breast cancer tumors detected when still small (less than 1 cm) was lower in the BRCA1 group of women (~21%) compared to the other groups (~40-64%).
Ductal carcinoma in situ was detected more frequently in women with a family history of breast cancer and in women with the BRCA2 gene mutation than women with the BRCA1 gene mutation.
Distant metastasis-free survival (84%) and overall survival (93%) of BRCA1/2 gene mutation carriers with invasive breast cancer after 6 years of follow-up was high.
100% of women at high risk for breast cancer due to family history survived during the 6 years of follow-up.
These are important results for women at high risk for breast cancer for a couple of reasons. First, it is clear from this study that women carrying the BRCA1 gene mutation generally appear to be at greater risk for the detection of more advanced breast cancer (mammograms were less sensitive and apparently the detected tumors were generally larger) than other women at high risk for breast cancer. This is important when determining appropriate breast cancer prevention strategies for these women.
Second, these study results suggest that the incorporation of MRI as part of a high risk woman's breast cancer screening program might improve survival. While a control group that did not receive MRI screenings was not available in this study for direct comparison since it would be unethical not to provide the screenings for women at high risk for breast cancer, a story in the New York Times indicates that the study authors reported that previous studies in which MRI screenings were not used had a 5-year survival rate of only 74%, much lower than the 84-93% survival seen in this new study. While it has generally been believed that earlier detection of breast cancer with MRI screening in high risk women would lead to improved chances of survival, this is apparently the first study to confirm this belief. It is clear from this study that the inclusion of annual MRI screenings in addition to annual mammograms and clinical breast exams can be an important part of a breast cancer screening program for women at high risk for breast cancer.