Background: Digital mammography (DM) and digital breast tomosynthesis (DBT) are important radiological modalities, which increase the survival of breast cancer patients. Breast cancer is a morphologically heterogeneous disease with various histopathological parameters and multiple receptors in its biological profile. Objectives: This study aimed to analyze the morphological features of invasive breast cancer on DM and DBT, to investigate the contribution of DBT to DM, to examine the association of DBT findings with pathological molecular subtypes, Bloom-Richardson grade, and Ki-67 index, and to determine the effect of breast parenchyma density on the relationship between DBT findings and hormone receptors. Patients and Methods: A total of 36 patients with malignant lesions were evaluated in this study. According to the American College of Radiology (ACR) classification, the lesion features were divided into subgroups based on DM and DBT, and the findings were compared. The relationships between DBT findings and the hormone receptor status, molecular classification, and Bloom-Richardson grade were also investigated, and the effect of density on these relationships was assessed. Results: The mean age of the patients (n = 36) was 53 years. Based on the comparison of DM and DBT findings, spiculated margins, mass density, architectural distortion, and microcalcifications were significantly more frequent in DBT. Lesions with indistinct margins on DM were observed as mass lesions with spiculated margins on DBT (P < 0.001). Regarding the relationship between DBT findings and hormone receptor status and Ki-67 proliferation index, in PR-positive patients, an irregular tumor shape was more common (89.7%). In PR-negative patients, skin changes and nipple retraction were more frequently seen (P = 0.03 for skin changes, and P = 0.049 for nipple retraction). Regarding the association between Bloom-Richardson grade and DBT findings, tumors with a higher grade were more likely to be associated with a high tumor density (P = 0.032). Also, considering the relationship between molecular classification and DBT findings, skin changes and nipple retraction were significantly more frequent in triple-negative masses compared to other subtypes (P = 0.011 for skin changes and P = 0.016 for nipple retraction). Conclusions: DBT is superior to DM, as it reveals the lesion margins, density, and architectural distortion more accurately. The majority of PR-positive tumors were irregular, while most PR-negative cases were round. The mass density also increased as the tumor grade increased. Skin change and nipple retraction were frequently seen in triple-negative tumors compared to other subtypes. Therefore, DBT is a promising diagnostic tool for showing molecular subtypes in dense breasts.

Background: Digital mammography (DM) is one of the most common and effective radiological methods for breast cancer screening and detection. A dense fibroglandular breast tissue can lead to false negative results by superimposing on the lesion margins. Therefore, adjunctive imaging methods, such as digital breast tomosynthesis (DBT) and ultrasonography (US), are needed to increase mammographic sensitivity. Objectives: This study aimed to examine the contribution of US and DBT to DM in different patient groups (patients group of BI-RADS 0 and 3-4 lesions, patients with dense breast parenchyma, patients with non-dense breast parenchyma).. Whether US and DBT can upgrade or downgrade the BI-RADS category of uncertain lesions detected on DM was also investigated. Patients and Methods: Forty-six patients, who were classified as BI-RADS categories 0, 3, and 4 in DM, according to DBT and US findings, were included in the study. DM followed by DBT was performed for the patients, and the BI-RADS classification system was applied. Subsequently, the patients were evaluated sonographically, and the BI-RADS system was applied according to the US results. Each BI-RADS category was compared with the histopathological and multimodality follow-up results. The diagnostic performance of all modalities was also examined alone and in combination. Results: The sensitivity and specificity of DM alone was 42% and 87%, respectively. DBT detected the lesions with 92% sensitivity and 68% specificity. The modality with the highest sensitivity for the detection of malignant lesions was US (100%). Besides, the specificity of DBT was significantly high for dense breasts (P < 0.001). There was no significant difference in terms of the diagnostic accuracy of US measurements between dense and non-dense breasts. For indeterminate lesions, the integration of DBT and US to DM increased the diagnostic accuracy. Conclusion: The contribution of DBT is more valuable than US in patients with dense breast parenchyma.