Sentinel lymph node micrometastasis and risk of non-sentinel lymph node metastasis: validation of two breast cancer nomograms

Abstract

Introduction: The aim of this study is to validate the predictive value of the Memorial Sloan-Kettering Cancer Center (MSKCC) nomogram and the Tenon score system in our sentinel lymph node (SLN)-positive series, and to define their actual usefulness when applied to the subgroup of patients with micrometastasis in SLN.

Patients and methods: The study population consisted of 95 patients: 68 with macrometastasis and 27 with micrometastasis in the SLN. The predicted probability of non-SLN metastasis was calculated for each patient by using a computerized model from the MSKCC Web site. Furthermore, we have applied the Tenon score to our dataset. The receiver operating characteristic (ROC) curves were drawn and the areas under the curve (AUCs) were calculated to assess the discriminative power of the nomograms. The ROCs and relative AUCs were calculated both for all the patients in the study and for 2 subgroups.

Results: The AUC for the entire study population was 0.720 in MSKCC nomogram: and 0.754 in Tenon nomogram. In 68 patients with macrometastasis in SLN, the AUC was 0.760 in MSKCC nomogram and 0.707 in Tenon score. Micrometastasis in SLN were found in 27 patients: AUC was 0.595 in MSKCC nomogram and 0.734 in Tenon score.

Conclusion: In our results the MSKCC nomogram did not provide a reliable predictive model for identifying patients with low risk of non-SLN metastasis in the event of micrometastasis in SLN. Our validation study shows that the Tenon score is more accurate and useful in patients with micrometastasis in SLN.