Association between axillary lymph node status and Ki67 labeling index in triple-negative medullary breast carcinoma

Objective: Medullary breast carcinoma is a rare breast carcinoma with good prognosis. Although it has been established that axillary lymph node metastasis is a poor prognostic factor, little is known about the relationship between axillary lymph node metastasis and clinicopathological characteristics of medullary breast carcinoma patients. The aim of this study was to identify factors that predict occurrence of axillary lymph node metastasis in medullary breast carcinoma patients. Methods: We performed a retrospective study of axillary lymph node status and the relevant clinicopathological characteristics in 49 triple-negative medullary breast carcinoma patients with axillary lymph node dissection between November 2004 and July 2011. Results: A total of 49 patients were enrolled in the study. Fourteen patients (28.6%) had axillary lymph node metastasis that was confirmed pathologically. Axillary lymph node metastasis was not associated with age, menopausal status, primary tumor size or its location, the degree of inflammation within the tumor or mitotic count. However, we found a statistically significant association between axillary lymph node metastasis and Ki67 labeling index in primary tumors (P < 0.001). Conclusions: There is a positive association between Ki67 labeling index in the primary tumor and axillary lymph node metastasis in triple-negative medullary breast carcinoma patients.