Needle-based confocal laser endomicroscopy of pancreatic cystic lesions: a prospective multicenter validation study in patients with definite diagnosis.

BACKGROUND:  Needle-based confocal laser endomicroscopy (nCLE) enables observation of the inner wall of pancreatic cystic lesions (PCLs) during an endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). This study prospectively evaluated the diagnostic performance of nCLE for large, single, noncommunicating PCLs using surgical histopathology or EUS-FNA cytohistopathology as a reference diagnosis.

METHODS:  From April 2013 to March 2016, consecutive patients referred for EUS-FNA of indeterminate PCLs without evidence of malignancy or chronic pancreatitis were prospectively enrolled at five centers. EUS-FNA and nCLE were performed and cystic fluid was aspirated for cytohistopathological and carcinoembryonic antigen (CEA) analysis. The diagnostic performance of nCLE was assessed against the reference standard and compared with that of EUS and CEA. This study was registered on ClinicalTrials.gov (NCT01563133).

RESULTS:  206 patients underwent nCLE and 78 PCLs (mean size 40 mm, range 20 - 110 mm) had reference diagnoses (53 premalignant and 25 benign PCLs). Post-procedure pancreatitis occurred in 1.3 % of the patients. nCLE was conclusive in 71 of the 78 cases (91 %). The sensitivies and specifities of nCLE for the diagnosis of serous cystadenoma, mucinous PCL, and premalignant PCL were all ≥ 0.95 (with 95 % confidence interval from 0.85 to 1.0). The AUROC was significantly larger for nCLE than for CEA or EUS.

CONCLUSIONS:  nCLE had excellent diagnostic performance that surpassed that of CEA and EUS for the diagnosis of large, single, noncommunicating PCLs. The nCLE procedure should be considered in patients with indeterminate PCLs to ensure a more specific diagnosis.