Prognostic influence of endoscopic ultrasound-guided fine needle aspiration in IPMN-derived invasive adenocarcinoma

BACKGROUND: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for mucinous cystic neoplasm of the pancreas carries a potential risk of inducing peritoneal tumor cell dissemination. We investigated the diagnostic yield and safety of EUS-FNA-based cytology of cells obtained from the pancreatic invasion site of intraductal papillary-mucinous neoplasm-derived adenocarcinoma (IPMC). METHODS: We included 22 surgically resected IPMCs and 84 pancreatic ductal adenocarcinomas (PDACs). Among the IPMC cases, 14 did not undergo EUS-FNA before surgical resection. The diagnostic yield of EUS-FNA was compared between IPMC and PDAC. Additionally, prognosis (relapse-free and overall survival time after resection) and the rate of peritoneal dissemination were compared among IPMC with EUS-FNA, IPMC without EUS-FNA, and PDAC. A survival analysis was performed using the Kaplan-Meier method and log-rank test. RESULTS: (EUS-FNA diagnosis) There were no significant differences in the number of needle passages (PDAC 2.5 vs. IPMC 2.0 passages, P = 0.84) or puncture route (stomach/duodenum: 2/6 vs. 45/39, P = 0.29). However, the correct diagnosis rate was significantly higher in PDAC (92.9%) than in IPMC (62.5%) (P = 0.03). No procedure-related adverse events occurred. Peritoneal lavage cytology performed during the operation was negative in all cases. (Prognosis) Among IPMC with EUS-FNA, IPMC without EUS-FNA, and PDAC, there were no significant differences in relapse-free survival (21.0 vs. 22.4 vs. 12.5 months, respectively; P = 0.64) or overall survival time (35.5 vs. 53.1 vs. 35.9 months, respectively; P = 0.42), and peritoneal dissemination was detected during the observation period in 25%, 28.5%, and 21.4% cases, respectively (P = 0.82). CONCLUSION: Even though a correct diagnosis was more difficult to obtain in IPMC than in PDAC, IPMC allows specimens to be obtained without influencing the rate of recurrence and prognosis.