P1.158. Clinical Performance of a Liquid Fiducial Marker for Preoperative Marking of the Optimal Resection Line in Gastroesophageal Cancer Surgery

Abstract

Abstract Topic Esophageal Cancer: Surgical Treatment of Esophageal Cancer Background Esophageal and gastroesophageal junction cancers have a poor prognosis despite improvements in curative treatment. Achieving microscopically cancer-free resection margins is essential for long-term outcomes, yet a substantial risk of microscopic positive margins remains. Neoadjuvant therapy can render tumors macroscopically undetectable, potentially increasing this risk. This study aimed to evaluate the performance and safety of a liquid fiducial marker for preoperative marking of the proximal resection margin before neoadjuvant oncological therapy. Methods This was a prospective cohort study. Participants scheduled for neoadjuvant oncological therapy and esophagectomy had the fiducial marker endoscopically implanted in the circumference of the esophagus, five cm proximal to the tumor, to mark the intended resection border. Marker placement was performed before the initiation of neoadjuvant therapy. During esophagectomy, the surgeon’s proposed proximal resection margin was marked, and intraoperative ultrasonography was used to locate the marker. The distance between the marking and the proposed resection line was measured. Results Ten participants were included. Technical success of marker injection was achieved in all cases, without adverse events. The mean implantation time was 214.6 seconds (±38.8). The marker was visualised intraoperatively in 70% of patients, and was seen as a hypodense, oval-shaped structure. The mean distance from the marker to the resection line was 30.7 mm (±22.1). Conclusion Preoperative placement of a liquid fiducial marker to delineate the esophageal resection margin was technically feasible and safe. In 70% of cases, the marker was identified intraoperatively using ultrasonography and was consistently located distal to or at the surgeon’s proposed resection line.