Second-screening mammography: one versus two views per breast.

To compare the advantages of one-view versus two-view second-screening (follow-up) mammography, oblique and craniocaudal projection mammograms from 1,000 consecutive asymptomatic women who had prior normal baseline studies were reviewed retrospectively, first with only the oblique images, then with the oblique and craniocaudal views. In women with dense breasts, one-view (oblique only) readings resulted in abnormal interpretations four times more frequently (53 cases, 5.3%) than two-view readings (13 cases, 1.3%). The induced cost from these abnormal interpretations would have more than offset the small savings in operating expense associated with one-view screening. In contrast, four times fewer abnormal one-view interpretations (13 cases, 1.3%) were made in women with primarily fatty breasts, in whom superimposition of dense tissue on images is not as frequently a problem. In these women, considering only cost, it may be reasonable to obtain a single mediolateral oblique projection for follow-up screening mammography. However, the issue of whether to implement such an approach remains unresolved, because the sensitivity of one-view versus two-view second screening in the detection of breast cancer has not yet been determined.