Objective: To identify the predictive factors of cancer invading into the nipple.
Methods: Patients with breast cancer undergoing mastectomy between May 2009 and March 2019 were reviewed retrospectively. Of these, those with breast cancer within 2 cm of the nipple areolar complex on ultrasonography were included in this study. Clinicopathological data of the primary tumor and imaging findings from mammography, ultrasonography, and MRI were compared between cases with and without nipple involvement by cancer.
Results: In total, 156 of the 821 patients identified were included in the analysis. Of them, 29 had nipple involvement by cancer. Univariate analysis revealed that the following imaging results were significantly associated with nipple involvement: perineural invasion, lymphovascular invasion, lymph node metastasis; relation type between the tumor and the nipple on ultrasonography; periareolar skin thickening on mammography; and short tumor-nipple distance, continuous enhancement between the nipple and tumor, skin enhancement, and nipple enhancement on MRI. However, on multivariate logistic regression analysis, only invasion type of tumor on ultrasonography and nipple enhancement and short tumor-nipple distance on MRI were significantly correlated with nipple involvement by cancer.
Conclusion: Imaging findings on preoperative mammography, ultrasonography and MRI are effective predictors for nipple involvement by cancer.
Advances in knowledge: Preoperative mammography, ultrasonography, and MRI help predict nipple involvement by breast cancer.