Full-field digital mammography compared with screen-film mammography in the detection of breast cancer: rays of light through DMIST or more fog?

Breast cancer is the most common malignancy and second most common cause of cancer death in women in the US [1]. To date, screen-film mammography (SFM) has been considered the gold standard for breast cancer screening and detection [1]. Over 70% of women in the US over the age of 40 have had a mammogram within the past 2 years [2]. Prior research has investigated the efficacy of SFM at reducing mortality from breast cancer [3–17]. While the interpretation of these results has been hotly debated [18–25], the consensus in recent systematic reviews and practice guidelines is that SFM reduces breast cancer mortality among women who are 50–75 years of age, and may reduce mortality among women aged 40 years and older [26–30]. A series of complex models supports the hypothesis that SFM has contributed to a reduction in breast cancer mortality in the US [31]. Although film mammography is the established diagnostic tool, it has a number of limitations. Breast cancer screening is less effective in younger women than in older women, most likely because younger women have a higher proportion of mammographically dense breast tissue [32– 35]. Up to a third of breast cancers are missed, even though as many as 20 women are called back due to false-positive results for every one cancer identified; this increases patient anxiety and leads to additional breast imaging, radiation exposure, and biopsies. Furthermore, with SFM, image acquisition, storage, and comparison can be cumbersome. As a result, much attention has been devoted to developing improved radiographic techniques for breast cancer screening and evaluation. Full-field digital mammography (FFDM) addresses some of the limitations seen with SFM. It has a wider range of contrast resolution, which holds particular promise for improving the detection of low-contrast lesions in radiographically dense breasts. FFDM allows for the separation of image acquisition, presentation, and storage, thus enabling these tasks to be independently optimized. The implementation of computer-aided detection methods is potentially simplified with FFDM, as there is no longer the separate step of digitizing film mammograms [36]. Computer-aided enhancement of images at computer workstations may also improve the accuracy of mammographic interpretation [37]. FFDM also has the potential to improve workflow by allowing for electronic transmission, storage, and retrieval of the images. Use of this modality may facilitate the interpretation of mammograms, as the images can be obtained locally, but sent to a central location for interpretation by experts at centers that specialize in mammographic interpretation. Digital storage and retrieval may increase the likelihood that comparison images from prior mammograms would be available to aid the radiologist in the interpretation of a new mammogram. Digital images can either be printed on film for review (hard copy) or read on computer monitors (soft copy). Digital image acquisition may improve the signal-to-noise ratio of X-ray detection over a wider range of intensities, as compared to that of film acquisition over the same range [38–40]. There is also the possibility of lower radiation exposure than that required for SFM. In spite of these potential advantages, adoption of a digital approach to mammography has been slow, in part due to the high spatial resolution required by J. A. Tice (&) M. D. Feldman Division of General Internal Medicine, Department of Medicine, University of California, 1701 Divisadero Street, Suite 554, San Francisco, CA 94143-1732, USA e-mail: jtice@medicine.ucsf.edu