The Inter- and Intra- Observer Agreement in Confocal Endomicroscopy Guided Diagnosis Of Pancreatic Cysts and Evaluation of Diagnostic Accuracy Compared to Histopathology

Aims Previous studies have suggested that EUS-guided needle based confocal laser endomicroscopy (nCLE) can diagnose pancreatic cystic lesions (PCLs) with high accuracy, inter-observer agreement (IOA), and intra-observer reliability (IOR). However, prior studies were small, and didn’t use histopathology as the ‘reference standard’. We aimed to assess the IOA, IOR, and performance of EUS-nCLE for differentiating PCLs in a larger cohort.

Methods We used EUS-nCLE videos representative of the most common types of PCLs. Subjects with confirmed histopathology were recruited from three prospective studies [INDEX (single-center), CLIMB (multicenter), and CONTACT (multicenter)] conducted in the US and France. Videos were edited to a representative clip of <1 minute. Thirteen endosonographers (Europe=4, US=4, Asia=5) blinded to the final diagnosis participated in the study. Observers reviewed the same set of nCLE videos in different sequences between two phases separated by a 2-week washout period. Observers were first queried on PCL classification (mucinous vs. non-mucinous) and specific PCL diagnosis. Fleiss’s kappa (k) for IOA and Cohen’s k for IOR were interpreted using Landis and Koch interpretation.

Results Seventy-six nCLE patient videos were assessed (IPMN=37; mucinous cystic neoplasm (MCN)=14; serous cystadenoma (SCA)=9; pseudocyst=3; cystic neuroendocrine tumors (NET) or solid pseudopapillary neoplasm (SPN)=13). IOA (k=0.82) and IOR (k=0.82) were almost-perfect to differentiate mucinous vs. non-mucinous PCLs. Observers differentiated mucinous vs. non-mucinous PCLs with high sensitivity (95 %), specificity (94 %), and accuracy (95 %). For the diagnosis of individual cysts, IOA was almost-perfect for SCA (k=0.85); substantial for IPMN (k=0.72), and NET/SPN (k=0.73); and moderate for MCN (k=0.47), and pseudocyst (k=0.57). Diagnostic accuracy was highest for SCA (98 %) NET/SPN (96 %), and pseudocyst (96 %).

	IOA, kappa (95 % CI)	Sensitivity (95 % CI)	Specificity (95 % CI)	Accuracy (95 % CI)
IPMN	0.72 (0.64, 0.79)	84.4 (80.9, 87.4)	87.9 (84.9, 90.5)	(83.9, 88.2)
MCN	0.47 (0.35, 0.59)	57.1 (49.9, 64.1)	90.2 (87.9, 92.1)	84.1 (81.7, 86.3)
Cystic-NET or SPN	0.73 (0.64, 0.83)	80.5 (73.9, 85.7)	98.9 (97.9, 99.4)	95.8 (94.3, 96.8)
Pseudocyst	0.57 (0.36, 0.79)	87.2 (73.3, 94.4)	96.2 (94.8, 97.3)	95.9 (94.4, 96.9)
SCA	0.85 (0.76, 0.95)	94.9 (89.3, 97.6)	98.6 (97.6, 99.2)	98.2 (97.1, 98.8)

Conclusions There is high degree of agreement, reliability, and accuracy in nCLE-imaged guided diagnosis of most prevalent PCLs. This study provides continued evidence supporting the utilization of EUS-nCLE in the evaluation of PCLs.

Citation: Machicado J, Napoleon B, Lennon AM et al. OP69 THE INTER- AND INTRA- OBSERVER AGREEMENT IN CONFOCAL ENDOMICROSCOPY GUIDED DIAGNOSIS OF PANCREATIC CYSTS AND EVALUATION OF DIAGNOSTIC ACCURACY COMPARED TO HISTOPATHOLOGY. Endoscopy 2021; 53: S29.

Publication History

Article published online:
19 March 2021