PROSPECTIVE, MULTI-INSTITUTIONAL, REAL-TIME TARGETED NEXT-GENERATION SEQUENCING OF BILIARY SPECIMENS IMPROVES THE DETECTION OF NEOPLASTIC BILE DUCT STRICTURES

Background: Several studies have demonstrated targeted next-generation sequencing (NGS) of biliary brushings and/or biopsy specimens can improve the identification of neoplastic bile duct strictures. However, these reports have largely been limited to retrospective analyses, single institutional experiences, and/or utilized NGS panels that were insufficiently comprehensive to account for the diversity of neoplasms that can cause a neoplastic stricture. The aim of this study was to prospectively evaluate NGS on a multi-institutional cohort of patients with a bile duct stricture in real-time.

Methods: Among seven institutions within a 3-year period, 1208 biliary specimens from 754 patients were submitted for targeted NGS that included two panels: a 28-gene NGS panel with 167 fusion genes (n=218) and a 161-gene NGS panel with 823 fusion genes (n=536). The NGS results were correlated with clinical presentation, history of primary sclerosing cholangitis (PSC), pathologic findings and follow-up. A stricture was designated as benign or neoplastic based on diagnostic pathology and/or a clinical course of >12 months.

Results: The sensitivity and specificity of NGS of biliary specimens for neoplasia were 82% and 96%, respectively. In comparison, pathologic evaluation had a sensitivity of 49% and a specificity of 100%. The combination of NGS and pathologic evaluation improved the sensitivity of both assays to 88%. Moreover, the addition of NGS to pathologic evaluation improved the sensitivity of biliary brushings from 36% to 84% and biliary biopsies from 47% to 87%. An expanded NGS panel (161 genes and 823 fusion genes) also showed improved sensitivity from 73% to 87% over a more limited panel (28 genes and 167 fusion genes). Repeat pathologic and NGS testing was performed for 118 patients and overall sensitivity increased to 91% but maintained a high specificity of 94%. Among 96 PSC patients, NGS had an 84% sensitivity as compared to pathologic evaluation with a 30% sensitivity. Of note, no statistically significant differences were observed in the performance of NGS based on the location of the patient’s stricture.

Conclusions: Through a prospective, multi-institutional study, the combination of NGS and pathologic evaluation of both biliary brushings and biopsy specimens improved the detection of neoplastic bile duct strictures. Furthermore, targeted NGS increased the sensitivity of identifying neoplasia in PSC patients.