# Factors Affecting Axillary Lymph Node Involvement Based on Permanent Section Evaluation of the Excised Sentinel Lymph Nodes in Early-Stage Breast Cancer Patients: A Single-Center Retrospective Study

## TL;DR

This study identifies factors like tumor subtype and Ki-67 levels that influence lymph node involvement in early breast cancer patients.

## Contribution

The study identifies Ki-67 as an independent risk factor and highlights the Luminal B subtype's association with sentinel lymph node positivity.

## Key findings

- Sentinel lymph node biopsy provides sufficient axillary staging in early breast cancer.
- Luminal B tumors are significantly associated with sentinel lymph node positivity.
- Ki-67 ≥ 14% increases sentinel lymph node metastasis risk by 5.2 times.

## Abstract

Background and Objectives: Sentinel lymph node (LN) biopsy (SLNB) remains to be the standard approach for surgical axillary staging of breast cancer (BC) patients. The aim of this study was to investigate the factors that affect axillary LN involvement in early BC patients. Materials and Methods: Clinically node negative early stage (cT1-2N0) BC patients having undergone breast conserving surgery (BCS) between February 2021 and January 2024 were included. During axillary exploration of all cases, sentinel LNs were excised and reserved for permanent section pathological examination (PS) only. Historical records of patients including clinicopathological features, surgical outcomes as well as pathological results were recorded and analyzed retrospectively. p < 0.05 indicated statistically significant results. Results: The study group consisted of 150 women with cT1-2N0 BC having undergone BCS with a median age of 59 (range: 25–81) years. According to the PS results of the sentinel LNs, the need for reoperation to complete axillary lymph node dissection was present in three (2%) patients. Tumors of the Luminal B subtype were significantly associated with increased sentinel LN positivity (p = 0.014). The risk of sentinel LN metastasis was found to be 5.2 times greater in patients with a Ki-67 ≥ %14 [OR: 5.224 (%95 CI:1.73–15.82, p = 0.003)] and the Ki-67 proliferation index was determined as an independent risk factor. Conclusions: In early-stage BC patients, PS of the excised sentinel LN offers sufficient axillary LN staging. On the other hand, a more careful clinical assessment is necessary for early BC patients harboring tumors with an elevated Ki-67 index and/or tumors of the Luminal B subtype.