Intraoperative diagnosis of lymph node metastasis during segmentectomy for non-small cell lung cancer by rapid immunohistochemistry using noncontact alternating current electric field mixing.

BACKGROUND Although lobectomy is considered the standard surgery for any non-small cell lung cancer (NSCLC), recent evidence indicates that for early NSCLCs segmentectomy may be equally effective. For segmentectomy to be oncologically safe, however, adequate intraoperative lymph node staging is essential. The aim of this study was to compare the results of a new rapid-IHC system to the HE analysis for intraoperative nodal diagnosis in lung cancer patients considered for segmentectomy. METHODS This retrospective study analyzed the pathological reports from NSCLC resections over a six-year period between 2014 and 2020. Using a new device for rapid-IHC, we applied a high-voltage, low-frequency alternating current (AC) field, which mixes the antipancytokeratin antibody as the voltage is switched on/off. Rapid-IHC can provide a nodal diagnosis within 20 minutes. RESULTS Frozen sections from 106 resected lymph nodes from 70 patients were intraoperatively evaluated for metastasis. Of those, five nodes were deemed positive based on both HE staining and rapid-IHC. In addition, rapid-IHC alone detected isolated tumor cells in one hilar lymph node. Three cStage IA patients with nodal metastasis detected with HE staining and rapid-IHC received complete lobectomies. Five-year relapse-free survival and overall survival among patients receiving segmentectomy with rapid-IHC were 88.77% and 88.79%, respectively. CONCLUSIONS Rapid-IHC driven by AC mixing is simple, highly accurate, and preserves nodal tissue for subsequent tests. This system can be used effectively for intraoperative nodal diagnosis. Rapid immunohistochemistry based on alternating-current field mixing (completed within 20 minutes) is simple and highly accurate. This system will assist clinicians when making intraoperative diagnoses of lymph node metastasis and deciding upon the appropriate surgical procedure in segmentectomy for lung cancer. KEY POINTS SIGNIFICANT FINDINGS OF THE STUDY: Rapid immunohistochemistry driven by alternating-current field mixing (completed within 20 minutes intraoperatively) is simple, highly accurate, and preserves lymph node tissue for subsequent pathological examination, including molecular assessments. WHAT THIS STUDY ADDS Segmentectomy for lung cancer is oncologically safe, but only when there is adequate intraoperative node staging. Rapid immunohistochemistry will assist clinicians when making intraoperative nodal diagnoses.