MA18.10 Multicenter Study of Intraoperative Rapid IHC for Undiagnosed Pulmonary Tumor Using Non-Contact Alternating-Current Electric-Field Mixing

It is widely recognized that pathology is the most important factor for staging and selecting effective chemotherapy for patients with cancer. Immunohistochemistry (IHC) is a reliable screening method, but intra-operative diagnosis by frozen section with IHC is not possible because IHC takes approximately 6 hours. Our aim was to evaluate the clinical utility reliability and sensitivity of a novel intraoperative rapid-IHC by taking advantage of the non-contact mixing effect in microdroplets subjected to an alternating current (AC) electric field. With the new device we have developed, we apply a high-voltage, low-frequency AC electric field to the sections. The antibody is mixed within the microdroplet as the voltage is switched on and off at specific intervals (Figure 1). The resultant coulomb force stirs the diluted solution on the sections, which increases the opportunity for contact. This rapid-IHC enables rapid detection of target cells in frozen sections and can provide a surgeon with an intraoperative diagnosis within 20 min. We will recruit total 150 patients with undiagnosed pulmonary tumor until December 2022. We enrolled 60 patients for now (the achievement rate is 40.0%). The rate of agreement between rapid-IHC and final pathological diagnosis was 95%. In contrast, the rate of agreement between conventional H&E stain and final pathological diagnosis was 83.3%. When diagnosing pulmonary tumor intraoperatively based on rapid-IHC, we achieved a higher performance level than was achieved using H&E stain alone. We have shown that the rapid-IHC can be used as a clinical tool for prompt diagnosis in pulmonary tumor samples. Our method will help pathologists and surgeons when diagnosing intraoperatively.