Endoscopic Ultrasound-Guided Confocal Laser Endomicroscopy Increases Accuracy of Differentiation of Pancreatic Cystic Lesions

Abstract

Background & aims Imaging patterns from endoscopic ultrasound (EUS)-guided needle-based confocal laser endomicroscopy (nCLE) have been associated with specific pancreatic cystic lesions (PCLs). We compared the accuracy of EUS with nCLE in differentiating mucinous from nonmucinous PCLs with that of measurement of carcinoembryonic antigen (CEA) and cytology analysis. Methods We performed a prospective study of 144 consecutive patients with a suspected PCL (≥20 mm) who underwent EUS with fine-needle aspiration of pancreatic cysts from June 2015 through December 2018 at a single center; 65 patients underwent surgical resection. Surgical samples were analyzed by histology (reference standard). During EUS, the needle with the miniprobe was placed in the cyst, which was analyzed by nCLE. Fluid was aspirated and analyzed for level of CEA and by cytology. We compared the accuracy of nCLE in differentiating mucinous from nonmucinous lesions with that of measurement of CEA and cytology analysis. Results The mean size of dominant cysts was 36.4 ± 15.7 mm and the mean duration of nCLE imaging was 7.3 ± 2.8 min. Among the 65 subjects with surgically resected cysts analyzed histologically, 86.1% had at least 1 worrisome feature based on the 2012 Fukuoka criteria. Measurement of CEA and cytology analysis identified mucinous PCLs with 74% sensitivity, 61% specificity, and 71% accuracy. EUS with nCLE identified mucinous PCLs with 98% sensitivity, 94% specificity, and 97% accuracy. nCLE was more accurate in classifying mucinous vs nonmucinous cysts than the standard method (P < .001). The overall incidence of postprocedure acute pancreatitis was 3.5% (5 of 144); all episodes were mild, based on the revised Atlanta criteria. Conclusions In a prospective study, we found that analysis of cysts by nCLE identified mucinous cysts with greater accuracy than measurement of CEA and cytology analysis. EUS with nCLE can be used to differentiate mucinous from nonmucinous PCLs. ClincialTrials.gov no: NCT02516488.