Validation of Memorial Sloan-Kettering Cancer Center nomogram for prediction of non-sentinel lymph node metastasis in sentinel lymph node positive breast cancer patients an international comparison

Abstract

Background: Current guidelines for breast cancer treatment recommend completion axillary lymph node dissection (CALND) following in case of positive sentinel lymph node (SLN) metastasis, which only in 35%-70% shows additional nodal metastases. Several nomograms and scoring systems have been created to predict the risk of metastasis in non-SLNs. The aim of the study was to identify individual patient risk for non-sentinel lymph node metastasis by validating with MSKCC nomogram and to evaluate the variability within a group of SLN-positive breast cancer patients with the final goal of avoiding unnecessary CALND.

Patients and methods: We retrospectively evaluated 1496 primary breast cancer patients. 324 women with a positive SLN who underwent CALND were identified. The predictive accuracy was measured and compared with the MSKCC nomogram by the area under the receiver operating characteristic curve. Receiver operating characteristic (ROC) curve was drawn on the basis of the sensitivity and specificity, and the area under the curve (AUC) was calculated.

Results: At least one metastatic non-SLN were identified in 88/324 (27.2%) patients. Tumor size, tumor type, tumor grade, number of positive SLNs and number of negative SLNs were significantly associated with non-SLN status in multivariate analyses. The MSKCC nomogram showed an AUC value of 0.738 (95% confidence interval = 0.682-0.793) after the validation for our collectives.

Conclusions: The MSKCC nomogram showed a good prediction for the non-SLN metastasis and performed adequately in our patient collective. Therefore, for the use of nomogram, validation with other populations of patients is strongly suggested.

Keywords: Breast cancer; Nomogram; Prediction of non-sentinel lymph node Metastasis.