Lesion Conspicuity in Contrast-Enhanced Mammography: A Retrospective Analysis of Tumor Characteristics

Background/Objectives: The aim of this study is to evaluate the impact of tumor characteristics on lesion conspicuity in contrast-enhanced mammography (CEM) and identify factors associated with different levels of conspicuity. Methods: In this retrospective study, we analyzed 552 patients with breast cancer who underwent CEM. Lesion conspicuity was categorized into three levels: 1 (low), 2 (moderate), and 3 (high). Tumor characteristics included age, histological subtype, hormone receptor status, HER2 status, Ki67 index, tumor grade, and molecular subtype. Univariate and multivariate analyses were conducted to assess associations between lesion conspicuity and these factors. Results: Of the 552 cases, the majority showed mass enhancement (78.1%), followed by non-mass enhancement (NME) (16.8%), and a combination of mass and NME (4.0%). Lesion conspicuity was significantly associated with enhancement type on CEM (p < 0.001). High conspicuity (score 3) was predominantly observed in masses (84.8%) compared to NME (7.6%). Larger tumor dimensions (median 20 mm) were also associated with higher conspicuity (p < 0.001). Molecular subtypes differed significantly in conspicuity, with Luminal A tumors showing lower conspicuity compared to HER2-positive and triple-negative breast cancers (p = 0.025). In multivariate analysis, lesion conspicuity was strongly associated with enhancement type (p < 0.001) and tumor dimensions (p < 0.001), while histological subtype and molecular characteristics had no significant independent impact. Conclusions: Lesion conspicuity in CEM is primarily influenced by the type of enhancement and tumor size. Mass-forming lesions, particularly larger ones, are more conspicuous, while NME tends to result in lower conspicuity. These findings suggest that enhancement patterns and tumor dimensions are key factors to consider when interpreting CEM in breast cancer diagnosis.