Diagnostic accuracy of directed cholangioscopic biopsies and confocal laser endomicroscopy in cytology-negative indeterminate bile duct stricture: a multicenter comparison trial.

BACKGROUND: The aim of this study was to assess the operating characteristics of using the confocal endomicroscopy miniprobe (pCLE) compared to cholangioscopic targeted biopsies for the detection of malignancy in biliary tract strictures. METHODS: We conducted a retrospective analysis of data of patients who underwent evaluation of indeterminate biliary strictures after inconclusive brush cytology. Only those patients with a final pathologic diagnosis or a conclusive >12 months follow-up were included. Patients were divided into 2 groups: those who underwent pCLE assessment (pCLE) and those who underwent cholangioscopic targeted biopsies (SB) of biliary strictures. Cholangioscopic biopsies were considered positive for malignancy when adenocarcinoma cells were identified. pCLE was considered positive for malignancy according to the Miami and Paris criteria. RESULTS: A total of 195 patients (median age, 66 years; 54.9% male) were included; 61 underwent C-pCLE and 134 underwent SB. Patient and biliary stricture characteristics were similar in the 2 groups. Final diagnoses were cholangiocarcinoma (N.=93), pancreatic adenocarcinoma (N.=6); and benign strictures (N.=96). The overall sensitivity of pCLE and SB for the detection of malignancy were 76.4% and 78.4% respectively (P=0.7). Similarly, there was no difference in the specificity of pCLE and CB for the diagnosis of malignancy (97.7% and 98.5% respectively; P=1). The diagnostic accuracy of pCLE was 83.6% versus 88.8% in SB (P=0.8). However, the specificity to detect a malignancy was higher for CB compared to pCLE (98.5 vs. 86.3%; P=0.04). CONCLUSIONS: In patients with indeterminate bile duct strictures, cytology combined with pCLE has a similar sensitivity, and diagnostic accuracy when compared to cholangioscopic biopsies for the diagnosis of malignant strictures. pCLE may be beneficial for in vivo, real-time histopathologic examination of biliary strictures and help in the instantaneous characterization of biliary strictures.