Evaluation of Screening Whole-Breast Sonography as a Supplemental Tool in Conjunction With Mammography in Women With Dense Breasts

Objectives-The purpose of this study was to evaluate the use and performance of supplemental screening whole-breast sonography in conjunction with mammography in asymptomatic women with dense breast tissue. Methods-A total of 28,796 asymptomatic women underwent screening mammography. Among 20,864 women with dense breasts (72%), 8359 underwent additional sonography as part of their screening examinations. We classified women with mammographically dense breasts into mammography-only and mammography-plus-sonography groups. The reference standard was a combination of pathologic results and clinical follow-up at 2 years. We compared the recall rate, cancer detection yield, sensitivity, specificity, and positive predictive value in each group. Results-Among the 20,864 women with dense breasts, 35 cancers were diagnosed, with a mean size of 13 mm. The cancer detection yield was 0.480 per 1000 women in the mammography-only group and increased to 2.871 in the mammography-plus-sonography group. Of 24 cancers detected in the mammography-plus-sonography group, the mean size was 11 mm, and the axillary lymph nodes were negative in 19 of 20. The sensitivity was significantly higher in the mammography-plus-sonography group than the mammography-only group (100% versus 54.55%; P = .002). The positive predictive values of sonographically prompted biopsy were 11.1% for the mammography-plus-sonography group and 50% for the mammography-only group. Conclusions-Supplemental screening whole-breast sonography increases the cancer detection yield by 2.391 cancers per 1000 women with dense breast tissue over that of mammography alone. It is beneficial for increased detection of breast cancers that are predominantly small and node negative; however, it also raises the number of false-positive results.