Which Needle Needs to Be Chosen for Better Outcome of Endoscopic Ultrasound-Guided Tissue Acquisition?

Abstract

Endoscopic ultrasonography (EUS) has been used in clinical medicine for almost 40 years. During this period, EUS has become an essential tool for gastrointestinal endoscopy. The development of the linear EUS scope enabled not only direct visualization of the lesions along the path of the scope but also EUSguided tissue acquisition (EUS-TA). Nowadays, EUS-TA serves as one of the best diagnostic choices in many diseases involving the gastrointestinal tract and its adjacent structures. EUS-TA is well known for its high accuracy and safety. However, several factors can affect outcomes of EUS-TA. The endosonographer’s experience, the size and location of the lesion, the size and type of the needle, the specific techniques of the procedure, the presence of a cytopathologist for rapid on-site examination, and the cytologist’s expertise are some of the important factors that can influence procedure outcomes. In EUS-TA, needles are used for EUS-guided fine-needle aspiration (FNA) and EUS-guided fine-needle biopsy (FNB). Cytological samples obtained by EUS-FNA provide relatively high diagnostic accuracy, but cytological evaluation alone without histology sometimes has limitations in confirming diagnoses. A meta-analysis of the diagnostic performance of EUS-FNA for a solid pancreatic mass showed pooled sensitivity of 87% and pooled specificity of 96%. FNB needles are better to obtain tissue cores than FNA needles. Tissue cores with preserved architecture and immunohistochemical stain are beneficial for the diagnosis of a few specific diseases, such as mesenchymal tumors, well differentiated adenocarcinomas, lymphomas, cancers in chronic pancreatitis, and autoimmune pancreatitis. In addition, with the rise of personalized medicine, it is now necessary to obtain more tissue for next-generation sequencing, molecular analysis, and organoid generation. Initially, the 19-gauge Tru-Cut biopsy needle was developed to harvest core tissues. However, this needle presented a host of issues, such as elevated procedure costs and complication rates, difficulty in manipulation, and difficulty in using the transduodenal approach. The EchoTip ProCore (Wilson-Cook Medical, Winston-Salem, NC, USA) FNB needle was introduced to correct and better serve Tru-Cut needle’s identified shortfalls. The 19/22/25-gauge ProCore needle comes with a reverseside-bevelled architecture at its tip that facilitates core tissue sampling. Although a significant number of studies have evaluated the performance of the ProCore needle, most studies have not been able to prove its superiority with respect to diagnostic accuracy over the EUS-FNA needle. A meta-analysis showed no significant differences in diagnostic adequacy (75.2% vs 89.0%: odds ratio [OR], 0.39; p=0.23), diagnostic accuracy (85.8% vs 86.2%: OR, 0.88; p=0.53), or histological core specimen acquisition (77.7% vs 76.5%: OR, 0.94; p=0.85) between the 19-gauge ProCore and EUS-FNA needles. However, ProCore needles had a lower mean required number of needle passes for diagnosis than did EUS-FNA needles (standardized mean difference, 1.2; p<0.001). Recently, a 20-gauge antegrade-cutting-side-bevelled biopsy needle (ProCore) was developed for EUS-TA. In this issue of Gut and Liver, Fujie et al. reported their research results in a study entitled “Comparison of the diagnostic yield of the standard 22-gauge FNA needle and the new 20-gauge forwardbevel FNB needle for EUS-TA from pancreatic lesions.” This