Predictors of positive axillary lymph nodes after sentinel lymph node biopsy in breast cancer

Objective: The purpose of this study was to determine the factors that predict the presence of metastasis in nonsentinel lymph nodes (SLN) when the SLN is positive. Methods: A prospective database was analyzed and included patients who underwent SLN biopsy for invasive breast cancer from July 1997 to August 2000 (n = 442). One hundred (22.6%) patients had one or more positive SLNs, and were analyzed to determine factors that predicted additional positive axillary nodes. Results: Of the 100 patients with a positive SLN, 40 patients (40%) had additional metastasis in non-SLNs. The only significant variables that predicted non-SLN metastasis were tumor lymphovascular invasion (P = 0.004), extranodal extension (P < 0.001), and increasing size of the metastasis within the SLN (P = 0.011). In analyzing just those patients who had lymphovascular invasion, extranodal extension, and a SLN metastasis > 2mm, 92% were found to have additional positive nodes. Conclusions: In patients with invasive breast cancer and a positive sentinel lymph node, lymphovascular invasion, extranodal extension, and increasing size of the metastasis all significantly increase the frequency of additional positive nodes. (C) 2001 Excerpta Medica, Inc. All rights reserved.