Breast cancer screening in women at high risk using MRI.

A series of prospective comparative studies have demonstrated that MRI has approximately twice the sensitivity of X-ray mammography for screening women at high familial risk of breast cancer. In these studies, lesions have often been detected at an early stage, with disease being small and predominantly node negative. The diagnostic features in relation to risk and the biological behaviour of disease with risk category and age are being evaluated. The results of these studies have resulted in revised recommendations for screening for women at high risk of breast cancer. In this article, the results of the UK Magnetic Resonance Imaging in Breast Cancer Screening (MARIBS) study of MRI screening are described, and compared with results from other studies. Risk factors identifying women who would benefit from MRI screening are discussed, MRI measurement methods are described, and the results of studies evaluating MRI and mammographic lesions in different risk groups are reviewed. Recommendations for screening women at high risk of breast cancer published by the American Cancer Society and from the National Institute for Health and Clinical Excellence (NICE) in the UK are summarised.