Optimal indication of endoscopic retrograde pancreatography-based cytology in the preoperative pathological diagnosis of pancreatic ductal adenocarcinoma.

BACKGROUND: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is extremely useful for pathological diagnosis of pancreatic ductal adenocarcinoma (PDAC); however, puncturing is difficult in some cases, and there is a risk of needle tract seeding. This study evaluated the indications for endoscopic retrograde pancreatography-based (ERP)-based cytology for the preoperative diagnosis of PDAC. METHODS: This study included 267 patients with PDAC who underwent preoperative ERP. The diagnostic performance of ERP-based cytology for PDAC was evaluated based on the sample collection method (pancreatic juice cytology [PJC] during ERP, brush cytology, PJC via endoscopic nasopancreatic drainage [ENPD] catheter), lesion site (pancreatic head, body/tail), and lesion size (≤10 mm, 10-20 mm, >20 mm), and compared with the diagnostic performance of EUS-FNA. RESULTS: The overall sensitivity of ERP-based cytology was 54.9%; sensitivity by the sampling method was 34.7% for PJC during ERP, 65.8% for brush cytology, and 30.8% for PJC via an ENPD catheter. The sensitivity of EUS-FNA was 85.3%. Brush cytology and PJC via an ENPD catheter were performed more often in pancreatic body/tail lesions than in head lesions (P = 0.016 and P < 0.001, respectively), and the overall sensitivity of ERP-based cytology was better for body/tail lesions (63.2% vs. 49.0%, P = 0.025). The sensitivities of ERP-based cytology and EUS-FNA in diagnosing PDAC ≤10 mm were 92.3% and 33.3%, respectively. Post-ERP pancreatitis was observed in 22 patients (8.2%) and significantly less common with ENPD catheters (P = 0.002). CONCLUSIONS: ERP-based cytology may be considered the first choice for pathological diagnosis of PDAC ≤10 mm and in the pancreatic body/tail.