The predicted probability of having positive non-sentinel lymph nodes in patients who received neoadjuvant chemotherapy for large operable breast cancer

Abstract

The accuracy of the nomogram in women with positive sentinel nodes following neoadjuvant chemotherapy (NCT) is unknown. The aim of this study was to evaluate the accuracy of the nomogram in patients receiving NCT. Between December 1999 and December 2005, we identified 233 patients who had a positive sentinel lymph node biopsy (SLNB) and complete axillary lymph node dissection at Magee-Womens Hospital of University of Pittsburgh Medical Center. Thirty-two patients (14%) had presented with clinically N0 breast cancer (BC) for which NCT was administered. The computerised BC nomogram was used to calculate the probability of non-sentinel node metastases utilising tumour size before NCT and after NCT for the same patient. The discrimination of the nomogram was assessed by calculating the area under (AUC) the receiver operating characteristic curve (ROC). The median patient age was 51.5 (range: 39-66) years in the NCT group of patients. Twelve patients (37%) had positive axillary non-sentinel lymph nodes (NSLNs). The nomogram was first validated in our institution for 201 patients without NCT and the predicted accuracy of the nomogram by the AUC was 0.73. The area under the ROC was identical regardless of whether pre- or posttreatment tumour size was used to determine predicted probability of NSLN metastases (0.66). The predictive accuracy of the nomogram was found to have less power for patients receiving NCT (0.66) than the non-NCT group of patients.