Background: The predictive probability of breast cancer nomograms for non-sentinel node metastases (NSLNM) after neoadjuvant chemotherapy (NCT) in patients with a positive sentinel lymph node (SLN) biopsy is unknown. The aim of this study was to evaluate the accuracy of 3 different nomograms in patients receiving NCT.
Patients and methods: Between 1999 and 2007, 54 patients presented with clinically N0 disease received NCT. Nomograms developed by Memorial Sloan-Kettering Cancer Center (MSKCC), Stanford University, and Tenon Hospital were used to calculate the probability of NSLNM by using tumor size at presentation and after NCT for the same patient. The discrimination of the nomograms was assessed by calculating the area under (AUC) the receiver operating characteristic curve, and it was accepted that AUC values 0.7-0.8 represent considerable discrimination.
Results: The median patient age was 50.9 years (range, 29-67 years). Twenty-two patients (38.8%) had positive NSLNM. The MSKCC and the Stanford nomograms yielded similar AUC regardless of whether initial or post-NCT tumor size was used to determine predicted probability of NSLNM (AUCs were < 0.70). AUC was 0.74 for the Tenon model using tumor size at presentation. After NCT, the AUCs were 0.64, 0.57, and 0.78 for the MSKCC, the Stanford, and the Tenon nomograms, respectively.
Conclusion: Although the AUC of the Tenon model was acceptable for accuracy, we found a lower rate for predicting negative NSLNM in our group than in the Tenon Hospital report. All of the nomograms developed for use in the non-NCT population need to be used with caution in the NCT population.