Endoscopic ultrasound is useful for the risk stratification of mucinous pancreatic cystic lesions: A long-term prospective study

Objectives: The aims of this prospective observational study were to test worrisome features on endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) as a stratification tool in patients with mucinous pancreatic cystic lesions (PCLs), and to assess these patients' long-term risk of adenocarcinoma and mortality.

Methods: Patients with suspected PCLs on cross-sectional imaging who underwent EUS-FNA at Sahlgrenska University Hospital between February 2007 and February 2018 were consecutively enrolled. The main inclusion criterion was the final diagnosis of a mucinous PCL. The results from EUS-FNA were analyzed in the context of outcome gathered from medical records of follow-up until February 2021.

Results: Of 334 patients undergoing EUS-FNA, 171 (51 %) had a final diagnosis of a mucinous PCL. 29/171 (17 %) patients were diagnosed with HGD or adenocarcinoma <6 months after EUS-FNA, with 28/29 (97 %) patients having at least one worrisome feature on EUS-FNA. A solid component in mucinous PCLs on EUS was independently associated with the presence of HGD or adenocarcinoma (OR 23.6, 95 % CI 6.1-91.6, p < .001). A total of 4/142 (3 %) patients developed adenocarcinoma during the follow-up period (median = 61.4 months). Overall, in 80/82 (98 %) of the patients without worrisome features on EUS-FNA, HGD or adenocarcinoma was not detected. Six of the 21 (29 %) patients with HGD or adenocarcinoma who underwent surgery as initial management died from pancreatic cancer during follow-up.

Conclusions: EUS-FNA is useful for the risk stratification of mucinous PCLs. The low incidence of adenocarcinoma over time after a negative EUS-FNA may allow for a less resource intensive surveillance strategy.