Sonographic characteristics of breast cancers detected by supplemental screening US: Comparison with breast cancers seen on screening mammography

Background: Supplemental screening ultrasonography (US) in addition to mammography can help detect early breast cancers in women with dense breasts and other risk factors. It is crucial to understand the imaging features of US-detected cancer to identify them in screening population. Purpose: To retrospectively evaluate the US features and final assessments of breast cancers detected by supplemental screening US in comparison with cancers seen on screening mammography. Material and Methods: The study included 80 women (mean age 46 years, range 31-65 years) with 80 breast cancers detected by supplemental screening US. Another 80 women (mean age 52 years, range 33-77 years) with 80 breast cancers seen on screening mammography were included for a control group. US features and final assessments were classified according to the Breast Imaging Reporting and Data System (BI-RADS) without knowledge of the method of detection, or mammographic or histologic findings. Results of the two groups were compared. Results: Breast cancers detected by supplemental screening US were more frequently found to have the following features: an oval shape (21% [17/80] vs 10% [8/80], P = 0.013), a circumscribed margin (13% [10/80] vs 4% [3/80], P = 0.043), an abrupt interface (79% [63/80] vs 53% [42/80], P < 0.001), and no posterior acoustic (70% [56/80] vs 53% [42/80], P - 0.023) or surrounding tissue (79% [63/80] vs 28% [22/80], P < 0.001) changes. For the final assessment, 93% (74/80) of US-detected cancers and 60% (48/80) of cancers seen on mammography were classified as a category 4, while 3% (2/80) of US-detected cancers and 38% (30/80) of cancers seen on mammography were category 5. Conclusion: Compared with breast cancers seen on screening mammography, breast cancers detected by supplemental screening US tend to have less malignant US features, although most (95%) of them were classified as category 4 or 5.