EUS-guided Fine-Needle Biopsy for Diagnosis and Molecular Profiling of Extrahepatic Cholangiocarcinoma: a Single-Center Retrospective Study

Aims The most common cause of biliary stricture is malignancy, but histological confirmation is mandatory before performing invasive surgical interventions or chemotherapy. Moreover, the increasing use of targeted anti-cancer therapies based on tumor molecular profiling makes the quality of the sampling of the neoplastic tissue even more important. In this study, we aimed to investigate the performance of endoscopic ultrasound (EUS) guided fine-needle biopsy (FNB) in diagnosis of extra-hepatic biliary strictures. Additionally, we evaluated the adequacy of the tissue sample for molecular biology analysis.

Methods This is a retrospective single-center study. EUS-FNB procedures performed at our Unit from January 2022 to August 2023 were analyzed. Patients who underwent EUS-FNB of extrahepatic (peri-hilar or distal) biliary stricture without a pancreatic mass were included. Diagnostic yield was evaluated and, in case of samples diagnostic for biliary malignancy, adequacy for molecular profiling (ie,>100 neoplastic cells) was also reported. Final diagnosis was obtained from surgical specimens or clinical/radiological follow-up.

Results During the study period, 34 patients underwent EUS-FNB for biliary stricture in absence of pancreatic mass at cross-sectional image. Among these, 29 patients underwent EUS-FNB of the biliary stricture (22 males, 75.9%; median age 75 years, range 48-92 years) and were included in the analysis, while 5 patients underwent sampling of a peri-biliary adenopathy, as the primary lesion was not reachable by the EUS-guided sampling. Eighteen patients had a peri-hilar stricture, while 11 had distal stricture. EUS-FNB was performed with 22G Franseen needle in 26/29 patients (89.6%), with 25G Franseen needle in 2/29 (6.9%) and with 22G and 25G Franseen in 1 patient (3.4%), with a median of 3 passes (range 1-6). At the final diagnosis, 24/29 (82,7%) had cholangiocarcinoma. EUS-FNB showed overall sensitivity of 68% (95% CI 46.5% – 85.0%) and diagnostic accuracy of 72.4% (95% CI 52.8% – 87.3%). Sensitivity and diagnostic accuracy for EUS-FNB of peri-hilar stricture were 70.6% (95% CI 44.0% – 89.7%) and 72.2% (95% CI 46.5% – 90.3%), respectively. Sensitivity and diagnostic accuracy for EUS-FNB of distal stricture were 62.5% (95% CI 24.5% – 91.5%) and 72.7% (95% CI 39.0% – 94.0%), respectively. In 2 false negative biopsies, final diagnosis of malignancy was obtained with concomitant EUS-FNB of hilar adenopathy in one case, and transpapillary biopsy during ERCP in the other. Overall, tissue samples were deemed adequate for molecular profiling in 10/16 (62.5%) of the cases positive for malignancy (peri-hilar 6/11, 54,5%; distal 4/5, 80%).

Conclusions In this retrospective study, EUS-FNB of biliary stricture showed overall good diagnostic yield for the diagnosis of cholangiocarcinoma. Moreover, EUS-FNB was adequate for molecular profiling in a relevant proportion of the cases positive for malignancy.

Publication History

Article published online:
15 April 2024