Study shows breast MRI increasingly used for screening high-risk women

Despite issues of expense, MRI is being increasingly used for breast cancer screening, diagnostic evaluation, treatment planning and surveillance but a recent study found that the indication for breast MRI has changed over time. Much of the increase was found among women with breast cancer risk factors, but there are still notable gaps in risk-based use.

The study (Wernli KJ et al. Patterns of breast magnetic resonance imaging use in community practice. JAMA Intern Med. 2014;174:125) used data on breast MRI and mammography collected by five United States national Breast Cancer Surveillance Consortium registries from 2005 to 2009. The researchers calculated the rate of breast MRI examinations per 1000 women with breast imaging within the same year and described the clinical indications for the breast MRI examinations by year and age. They also compared women screened with breast MRI to women screened with mammography alone for patient characteristics and lifetime breast cancer risk. The study included 8,931 breast MRI examinations and 1,288,924 screening mammograms from women aged 18 to 79 years. Researchers found that in this period the overall rate of breast MRI nearly tripled. The most common clinical indication was diagnostic evaluation (40.3 percent), followed by screening (31 percent). Compared with women who received screening mammography alone, women who underwent screening breast MRI were more likely to be younger than 50 years, white non-Hispanic, and nulliparous and to have a personal history of breast cancer, a family history of breast cancer, and extremely dense breast tissue.

Dr Tracy L. Onega, a co-author on the paper said “The benefit of breast MRI includes high sensitivity for identifying breast malignancy, and United States national guidelines support using it for particular clinical indications. But compared to mammography, breast MRI is more expensive and can lead to higher false positive rates. We need to continue to evaluate and compare the effectiveness of how MRI and mammography are used and find ‘the right test for the right woman at the right time’. The findings of our study suggest the continued need for evidence that will help align use of breast MRI”