A Nomogram to Predict Non-Sentinel Axillary Lymph Node Metastases in Breast Cancer Patients With Negative or Positive Sentinel Lymph Node Results

PurposePostoperative radiation therapy has been recommended as a replacement for axillary lymph node dissection (ALND) in patients with early-stage breast cancer who have one or two sentinel lymph node (SLN) metastases. This study aimed to develop a predictive model to assess the risk of intraoperative non-SLN metastases based on preoperative parameters.Materials and MethodsA retrospective analysis was conducted on 580 patients diagnosed with invasive breast cancer who underwent traditional ALND between January 2011 and June 2023 and were intraoperatively identified as SLN positive. The primary outcome of the study was non-SLN metastasis status. A nomogram prediction model was constructed to predict ipsilateral non-SLN metastases, and the optimal threshold value for SLN positivity rate was determined. Subgroup analysis was performed on hormone receptor (HR)-positive breast cancer cases to further refine the prediction model.ResultsThe optimal threshold for the SLN positivity rate in breast cancer eradication procedures was identified as 35.42%. Multivariate analysis of the entire cohort, as well as the HR-positive subgroup, revealed that histopathological grade, clinical T stage, clinical N stage, and a higher SLN positivity rate were significant risk factors for non-SLN metastases. The area under the receiver operating characteristic curve (AUC) of the nomogram prediction model was 0.809 for the entire cohort and 0.805 for the HR-positive subgroup, indicating robust calibration.ConclusionThe nomogram model developed in this study provides clinicians with a more accurate tool for predicting non-SLN metastases, potentially reducing unnecessary ALND procedures.