Influence of E-cadherin Expression on the Mammographic Appearance of Invasive Nonlobular Breast Carcinoma Detected at Screening

Purpose: To determine whether E-cadherin loss causes nonlobular cancers (NLCs) detected at mammographic screening to have different mammographic appearances than do NLCs with normal E-cadherin expression. Materials and Methods: This study design had hospital ethics committee approval; informed consent was waived. Membranous expression of E-cadherin was assessed immunohistochemically in patients younger than 70 years from a consecutive series of 1944 operable invasive breast cancers. Of those, 276 NLC cases (age range, 45-70 years) were common to a prospectively collected database of breast cancer detected at screening. The mammographic features of 131 NLCs with reduced E-cadherin expression were compared with those of 145 NLCs with normal E-cadherin expression. Results: NLCs with E-cadherin loss were more likely to manifest as an ill-defined mass and less likely to manifest noncomedo microcalcifications at mammography than were NLCs with normal E-cadherin expression (47 [35.9%] of 131 vs 35 [24.1%] of 145, P = .03; and one [0.8%] of 131 versus 13 [9%] of 145, P = .001; respectively). NLCs with E-cadherin loss were significantly larger (>= 15 mm) than NLCs with normal E-cadherin expression (71 [54.2%] of 131 NLCs vs 57 [39.3%] of 145; P = .01). Both groups had a similar distribution of grade, tumor type, nodal metastases, and vascular invasion. Conclusion: Invasive NLCs with reduced E-cadherin expression detected at screening are more likely to appear as ill-defined masses and less likely to manifest noncomedo microcalcifications than are NLCs with normal E-cadherin expression. NLCs with reduced E-cadherin expression appear to have mammographic features that make them difficult to detect at small sizes. (C) RSNA, 2009