Models for predicting non-sentinel lymph node positivity in sentinel node positive breast cancer: the importance of scoring system

Background: Although delayed axillary lymph node dissection is the gold standard for evaluating axillary status after identification of a positive sentinel lymph node (SLN), between 40% and 70% of sentinel lymph node positive patients will have negative non-sentinel nodes and undergo a non-therapeutic axillary dissection. Accurate estimates of the likelihood of additional disease in the axilla can assist decision-making about further treatment. To predict non-SLN metastases in patients with a positive SLN biopsy, four different nomograms have been created. Method: This paper reviews the scoring systems and nomograms reported in the literature and compares their predictive probability of non-SLN involvement in patients with SLN positive breast cancer. Result: There are several published scoring systems that contain different parameters to estimate the rate of non-SLN metastases in SLN positive patients. We reviewed Memorial Sloan-Kettering Cancer Center (MSKCC), Tenon, Stanford and Cambridge nomograms published and used scoring systems including three to eight variables. We found that the MSKCC nomogram is the most validated model in the literature to predict non-SLN status accurately. The other three models have not yet been verified in outside institutions. Conclusion: Despite having some limitations, the MSKCC nomogram is the most validated model in the literature. These models should be tested and verified in different programs and different patient groups before they are widely accepted.