Electrical lymph node scanning (ELS) system for real-time intra-operative detection of involved axillary lymph nodes in adjuvant breast cancer patients

Abstract

Lymph node (LN) status is an essential prognostic factor in breast cancer (BC) patients, with an important role in the surgical and therapeutic plan. Recently, we have been developed a novel system for real-time intra-operative electrical LN scanning in BC patients. The ELS scores were calibrated by pathological evaluation of the LNs. Herein, we evaluated the efficacy of ELS in a prospective study for non-chemo-treated breast cancer patients. This is a prospective study in which ELS scores are blind for pathologists who declare the clearance or involvement of LNs based on permanent pathology as the gold standard. ELS and frozen-section (FS) pathology results were achieved intra-operatively, and samples were sent for the permanent pathology. The score of ELS did not affect the surgeons' decision, and the treatment approach was carried out based on FS pathology and pre-surgical data, such as imaging and probable biopsies. Patients were recruited from October 2021 through November 2022, and 381 lymph nodes of 97 patients were included in the study. In this study we recruited 38 patients (39.2%) with sentinel lymph node biopsy (SLNB) and 59 patients (60.8%) with ALND. Of the 381 LNs scored by ELS, 329 sentinel LNs underwent routine pathology, while others (n = 52) underwent both FS and permanent pathology. ELS showed a sensitivity of 91.4% for node-positive patients, decreasing to 84.8% when considering all LNs. Using ROC analysis, ELS diagnosis showed a significant AUC of 0.878 in relation to the permanent pathology gold standard. Comparison of ELS diagnosis for different tumor types and LN sizes demonstrated no significant differences, while increasing LN size correlated with enhanced ELS sensitivity. This study confirmed ELS's efficacy in real-time lymph node detection among non-chemo-treated breast cancer patients. The use of ELS's pathological scoring for intra-operative LN diagnosis, especially in the absence of FS pathology or for non-sentinel LN involvement, could improve prognosis and reduce complications by minimizing unnecessary dissection.

Keywords: Breast cancer surgery; Electrical impedance spectroscopy (EIS); Impedance phase slope (IPS); Nodal staging; Pathology.

Figure 1

A schematic of ELS device.

Figure 2

Flowchart of patients.

Figure 3

(a) Classification criteria of ELS for non-chemo-treated patients discussed in. (b) IPS-Z_1kHz diagram of ELS in 381 LNs of non-chemo-treated patients according to their pathological evaluations showing complete discrimination between free and involved LNs. (c) AUC and ROC for ELS in LNs detection. The reference line is belonged to the permanent pathology as the gold standard. (d) Sensitivity, Specificity, Accuracy, Positive, and Negative Predictive Values of ELS results by cancer types. (e) Sensitivity, Specificity, Accuracy, Positive, and Negative Predictive Values of ELS results by estimated LN size categories. (f) Sensitivity, Specificity, Accuracy, Positive, and Negative Predictive Values of ELS results by TNM (As sample size in N3 type is 3, the comparison was done between three other groups).