Aims: To characterize the various clinicopathologic features in cases of breast cancer with positive sentinel lymph nodes (SLNs), in order to determine factors that might help in predicting the involvement of the non-SLNs.
Methods: A retrospective database review was performed of 726 breast cancer patients with stage 0-II, in whom SLNs were successfully identified. One hundred eighty-five of these patients showed positive SLNs, and subsequently underwent axillary lymph node dissection (ALND). These cases were divided into two groups based on the presence or absence of metastases in the non-SLNs, i.e. positive non-SLNs (NSLN+; 81 cases) and negative non-SLNs (NSLN-; 104 cases).
Results: Multivariate analysis revealed that a larger size of the primary tumour (>2.0cm), presence of lymphatic invasion, larger size of the largest SLN metastasis (>2mm), and a 100% metastatic rate in the SLNs (number of positive SLNs/number of harvested SLNs) were significantly associated with NSLN+. Among the cases in which all the four factors were present, 73% (30/41) were found to have NSLN+.
Conclusion: We found four independent predictors in relation to non-SLN metastasis. Although these factors might be useful for determining the need of additional ALND, it would seem that even the presence of all of these four factors in combination may be insufficient to safely omit ALND. Thus, until further evidence is accumulated from the results of large clinical trials, ALND would still be recommended for patients with SLN metastasis.