Endoscopic Ultrasound-guided Fine-needle Biopsy for Tissue Sampling of Biliary Strictures: a Multicenter Prospective Study

After the disappointing results of first-generation reverse bevel fine-needle biopsy (FNB) needles, newer 'third generation' endoscopic ultrasound (EUS) needles were developed, known as the "end-cutting" needles. These needle types have shown excellent diagnostic accuracy (\>90%) in pancreatic masses and several other lesions, even without rapid on site evaluation (ROSE) and are not associated with increased adverse event incidence . The main design of end-cutting FNB needles are the Franseen type, which has three symmetrically distributed needle points and cutting edges, and the Fork-tip type which has 2 protruding asymmetrical sharp points and six distal cutting edges; however, other end-cutting needles are currently available such as the three-prong asymmetric tip needle and the Menghini tip needle. Given the significant increase in diagnostic accuracy and sensitivity observed in other abdominal lesions, these needles are expected to improve the diagnostic outcomes of EUS-FNB of "pure" biliary strictures although clinical data are still lacking. The aim of this study is to ascertain the impact of end-cutting FNB needles in the diagnostic algorithm of biliary strictures in absence of a clear pancreatic or abdominal mass. This is a multicenter international observational prospective study. Consecutive patients diagnosed with biliary strictures in absence of a pancreatic or abdominal mass will be assessed for eligibility. Patients with jaundice requiring decompression, will undergo endoscopic retrograde cholangiopancreatography (ERCP) with tissue sampling (brushing and/or biopsy) and biliary drainage, preferably in the same session immediately after EUS-FNB. Endoscopic ultrasound will be performed using a curvilinear array echoendoscope. FNB with 22G or 25G end-cutting needles will be performed. The size of the needles will be based on the personal choice of the endoscopist. Likewise, the sampling technique, whether using the "slow-pull", the "dry suction", or the "wet suction", will be based on the physician's choice. Three passes will be performed as per current guidelines. Specimens will be collected in 3 vials to allow for analysis according to needle pass; one for the first pass, one for the second pass, and one for the third and any eventual subsequent passes. The ROSE will not be available in this study. Primary outcome will be diagnostic sensitivity of EUS-FNB and 45 patients will be prospectically enrolled.