Abstract: Abstract Background: To investigate factors that predict involvement of non-sentinel lymph nodes(nSLNs) in patients with positive SLNs. Methods: We reviewed the records of all patients with invasive breast cancer who underwent SLN biopsy at our institution between May 1999 and September 2015. Multivariate analysis was used to identify clinicopathologic features in SLN-positive patients that predict involvement of nSLNs. Results: A total of 108 patients had a positive SLN and underwent completion axillary lymph node dissection. Multivariate analysis revealed that primary tumor >2cm(P=0.024), SLN metastasis >2mm(P=0.015), and lymphovascular invasion (P=0.001) were independent predictors of positive nSLNs. The more above variable the patient has, the higher the likelihood of positive nSLN is. Conclusions: The likelihood of positive nSLNs correlates with primary tumor size, size of the largest SLN metastasis, and presence of lymphovascular invasion. Detailed pathologic examination of the primary tumor and its SLN metastases may increase precision in the selection of patients for further axillary surgery.

Key words: axillary dissection, breast carcinoma, predictive factors, sentinel lymph node