The likelihood of additional nodal disease following a positive sentinel lymph node biopsy in breast cancer patients: validation of a nomogram

BACKGROUND: Sentinel lymph node (SLN) biopsy examination is the current modality for evaluating the axilla in breast cancer patients. A nomogram has been developed to predict the likelihood of non-SLN metastases after a positive SLN biopsy examination. The purpose of this study was to validate the nomogram in a community breast center. METHODS: A prospective database was used to identify breast cancer patients with a positive SLN biopsy examination who underwent a completion axillary lymph node dissection. The nomogram was used to calculate the probability of having non-SLN involvement, and was compared with the observed numbers. RESULTS: The observed incidence of non-SLN involvement showed excellent correlation with the nomogram predicted probability (chi-square test statistic = 5.87; P = .83). CONCLUSIONS: Predicting the risk of additional nodal metastases allows the surgeon and patient to make an individualized decision regarding the need for completion axillary lymph node dissection.