Clinicopathological factors and nomograms predicting nonsentinel lymph node metastases after neoadjuvant chemotherapy in breast cancer patients.

BACKGROUND: Studies have demonstrated the feasibility and accuracy of sentinel lymph node (SLN) biopsy after neoadjuvant chemotherapy (NAC) in breast cancer. Some SLN-positive patients have low risk of nonsentinel lymph node (non-SLN) involvement. Our goal was to determine clinicopathological factors correlating with the presence of non-SLN metastases in patients after NAC and to assess the validity of nomograms predicting additional axillary metastases.

METHODS: Patients with infiltrating breast carcinoma (n = 132) were studied prospectively. All patients received NAC. At surgery, SLN biopsy followed by axillary lymph node dissection was performed. Lymphatic mapping was done using the isotope method. Fifty-one patients were SLN positive.

RESULTS: In univariate analysis, tumor size (P = 0.016) and the size of SLN metastases (P = 0.0055) were significantly correlated with the presence of non-SLN metastases. In multivariate analysis, SLN macrometastases (P = 0.047) conferred significantly increased risk of non-SLN metastases. The Memorial Sloan-Kettering Cancer Center nomogram was not reliably predictive for non-SLN metastases (area under the receiver operating characteristic curve, AUC, of 0.542), whereas the MD Anderson (AUC 0.716) and Tenon scoring systems (AUC 0.778) were validated.

CONCLUSION: Our results suggest that clinicopathological factors predicting non-SLN involvement in SLN-positive patients with and without NAC are essentially the same. The risk of involvement may be assessed using existing nomograms, but additional large prospective studies are needed to determine their accuracy in patients after NAC.