Association Between Imaging Features Using the BI-RADS and Tumor Subtype in Patients with Invasive Breast Cancer

Background: Different molecular breast cancer subtypes present different biologic features, treatment options, and clinical prognoses. The breast cancer imaging phenotype may help precisely classify breast cancer in a non-invasive manner. Objective: To identify the association between the imaging and clinicopathologic features of invasive breast cancer according to the molecular subtype. Methods: We retrospectively reviewed the electronic medical records of 313 consecutive women with breast cancer who underwent surgery between March 2018 and February 2019. Preoperative imaging studies were also reviewed and the association between the clinicopathologic and imaging features was evaluated according to the molecular subtype. Results: On mammography, the presence of microcalcifications was correlated with the human epidermal factor receptor 2-positive subtype (67%, 14/21). Luminal A and B tumors were more likely to have a spiculated margin (57% [63/110] and 41% [34/81]), while human epidermal factor receptor 2-positive and triple-negative breast cancers were more likely to have an indistinct margin (56% [10/18] and 35% [17/48]). On ultrasonography, luminal A tumors were likely to be depicted as masses with an irregular shape (85%, 115/136) and spiculated margin (49%, 66/136). On magnetic resonance imaging, triple-negative breast cancer appeared as a mass (n=13) that frequently had an irregular shape (62%, 8/13) but was more likely to be oval or round (39%, 5/13) than other subtypes. Conclusion: Some imaging features on mammography, ultrasonography, and magnetic resonance imaging could be useful predictors of the molecular subtype of breast cancer and may aid precision medicine development for patients with breast cancer according to the subtype.