Phase 1 trial of lavage cytology collected with endoscopic ultrasound-guided fine-needle aspiration for preoperative pancreatic cancer

Background and study aims: Intraoperative peritoneal lavage cytology (CY) influences prognosis in pancreatic cancer, and positive findings may lead to aborted surgery. Staging laparoscopy is traditionally used when no distant metastases are evident. We developed a novel method to assess CY using endoscopic ultrasound (EUS) and conducted a Phase 1 trial to evaluate its safety. Patients and methods: This non-randomized, prospective Phase I1trial was conducted in three stages with safety monitoring after each stage. The study was approved by the institutional review board (2023-0-239) and registered (UMIN000052528). Nine patients with pancreatic ductal adenocarcinoma who were considering surgery were enrolled between September 2023 and August 2024. A 3F sheath was inserted into the upper abdomen under endoscopic and fluoroscopic guidance, followed by injection of 200 to 300 mL of saline. After postural adjustments and abdominal massage, transrectal EUS-fine-needle aspiration was used to aspirate pelvic fluid. Results: Median age was 68 years (range, 36-80); 77.8% were male. Resectability status: resectable/borderline/unresectable (considering conversion): 4/2/3. The procedure was successful in all cases, with a median aspirated volume of 32 mL (range, 10-125). No adverse events occurred, and all patients were discharged the next day. Conclusions: This novel EUS-guided lavage cytology method was safe and feasible. A Phase 2 trial is planned.