Performance of the Standard 22G Needle for Endoscopic Ultrasound-guided Tissue Core Biopsy in Pancreatic Cancer

Background & Aim: Endoscopic ultrasonography (EUS) and EUS-guided fine-needle aspiration (EUS-FNA) are considered good tools for the diagnosis of pancreatic cancer and for obtaining material for cytology or histology. The accuracy of EUS-FNA can rise to 85-95%, but it is lower in cases with a chronic pancreatitis background or with previous biliary stenting. We aimed to establish the diagnostic yield of the visible length of the core biopsy samples in pancreatic cancer by using one single type of standard 22G needle and to evaluate the factors which can influence the results. Method: EUS-FNA was performed by using a 22G standard needle on patients prospectively recruited with the suspicion of pancreatic masses on transabdominal ultrasound or CT scan over a period of eight months. The number of passes was limited by the length of the core obtained. The final diagnosis was based on EUS-FNA or hepatic biopsy for their metastasis or by follow up every three month by imaging methods. Results: The study included 118 patients. Previous stents were present in 10 patients and chronic pancreatitis features were found in 3 patients. The procedure sensitivity was 89% and the global accuracy was 89%. The presence of biliary stents did not impede the accuracy of results. The number of passes did not influence the results. Conclusions: The diagnostic rate of core biopsy by using 22G needles had a high accuracy and it is safe when the length of core dictates the number of passes. The presence of biliary stents did not influence the results. Abbreviations: AUC: area under the curve; EUS: endoscopic ultrasonography; EUS-FNA: fine needle aspiration under endosonographic guidance; FNA: fine needle aspiration; INR: international normalised ratio; OR: odds ratio.