A comparison of diagnostic utility of new endoscopic scraper combined cell block method and conventional brush catheter for biliary tract cancer

Background/Aims: The sensitivities of endoscopic trans-papillary pathologic diagnosis of biliary tract cancer (BTC) are unsatisfactory. Recently, the diagnostic utility of the endoscopic scraper device, Trefle for biliary stricture has been reported. The Trefle can be guided to the target biliary stricture over the guidewire and is as easy to use as the conventional brush catheter (CBC). This study evaluated the efficacy and safety of Trefle-assisted tissue acquisition combined cell block method and CBC cytology for biliary strictures due to BTCs. Methods: We retrospectively reviewed consecutive patients with biliary strictures in whom CBC cytology or Trefle-assisted tissue acquisition under endoscopic retrograde cholangiopancreatography was performed for suspected BTCs from January 2015 to June 2022 at our institution. Results: 173 patients (CBC group; n = 55, Trefle group; n = 118) were enrolled in this study. The sensitivity, specificity, and accuracy of CBC cytology for BTC were 68.3%/100%/76.4%. On the other hand, the sensitivity, specificity, and accuracy of Trefle-assisted tissue acquisition for BTC were 93.7%/95.7%/94.1%, showing superior sensitivity (p < 0.001) and accuracy (p = 0.002) compared to that of CBC. Conclusions: Compared to CBC cytology, Trefle-assisted tissue acquisition has superior diagnostic performance while maintaining procedural simplicity and is considered useful for diagnosing malignant biliary stricture.