Predictors of Non-Sentinel Nodal Involvement in Breast Cancer Patients with Positive Sentinel Nodes Undergoing Upfront Surgery

Background & Objective: Sentinel lymph node (SLN) biopsy is performed to stage the axilla in clinically node negative breast cancer (BC) and is converted to axillary lymph node dissection (ALND) if found to be positive for tumor metastasis. A significant proportion of positive SLN cases do not reveal any positive non-SLN (NSLN) emphasizing the need to evaluate other clinicopathological factors which could better predict NSLN involvement and avoid unnecessary ALND in a select group of patients. We aimed to find the correlation of clinicopathological features of primary BC, positive SLN and NSLN after ALND in order to identify factors that may help in predicting involvement of NSLN. Methods: One hundred thirty BC cases with positive SLN who underwent ALND at Aga Khan University (2010-2022) were retrospectively reviewed for clinicopathological features to assess their association with status of NSLN involvement. Results: On univariate analysis, positive SLN to total SLN ratio, axilla scoring system (ASS) score and area of the largest metastatic tumor focus appeared as significant factors. However, area of the largest metastatic tumor focus was the sole predictor to NSLN involvement on multivariate analysis (odds ratio: 1.01). Chi-square test was used to determine that NSLN positivity was significantly associated with a positive SLN to total SLN ratio of >0.6, area of largest metastatic focus of >50mm² and ASS score of >5.5. Conclusion: This study highlights the need to consider other pathological factors (in addition to macrometastasis) before making the decision of ALND after positive SLN.