Survival outcomes of screening with breast MRI in high-risk women

1508 Background: Mammography is the only imaging modality proven to reduce mortality from breast cancer. Over the past decade, magnetic resonance imaging (MRI) screening of women with increased risk of breast cancer ( > 20% cumulative life time risk) has been recommended. However, there is little evidence that supplemental screening with MRI improves survival. The purpose of this study was to compare survival outcomes of combined screening with MRI and mammography to screening mammography alone in women at increased risk for breast cancer. Methods: A total of 3,002 women at increased risk underwent at least two screening rounds between 2001 and 2005, with at least 5 years of follow-up. 1,534 women had combined screening (MRI and mammography), and 1,468 had screening mammography alone. Cancer detection yield and survival were determined in the two groups. Results: 60 women were diagnosed with breast cancer, 38 patients in the combined screening group and 22 in the mammography-only group. Cancer yield was 24.8 per 1000 (95% CI, 17.6-33.8) combined screening and 15.0 per 1000 (95% CI, 9.4-22.6) mammography-only. No interval cancers occurred in women undergoing combined screening, while 9 interval cancers were found in women undergoing only mammography screening. During a median follow-up of 10.8 years (range, 0.7-15.2), a total of 11 recurrences and 5 deaths (4 breast cancer cause and 1 unknown cause) were found. Of the 11 recurrences, 6 were in the combined screening group and 5 were in the mammography-only group. All deaths were in the mammography-only group. The Kaplan-Meier estimate for disease-free survival showed no statistically significant difference between the two groups ( P = .325). However, patients in the combined screening group had a significantly better overall survival compared with patients in the mammography-only group ( P = .002). Conclusions: Combined screening with MRI and mammography in women with increased risk of breast cancer resulted in not only a higher cancer detection yield but also better overall survival.