ASGE Therapeutic EUS for Advanced Endosonographers (Live and Virtual) | September 2022-1 Savides

1 Savides_EUS Guided Tissue Acquisition

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This document provides an overview of advances in EUS-guided tissue acquisition (EUS-TA) techniques. EUS-TA includes EUS fine needle aspiration (FNA) and EUS fine needle biopsy (FNB). The ideal EUS-TA techniques aim for high specimen adequacy, diagnostic yield, accuracy rate, and a low adverse event rate with minimal passes.<br /><br />Quality indicators for pancreatic EUS-TA were established in 2015, which include achieving a diagnostic rate of adequate samples, sensitivity for malignancy, and a low incidence of adverse events.<br /><br />Over the years, the goals of EUS-TA have evolved, with a focus on obtaining both cytologic and pathologic diagnoses as well as material for molecular and genetic characterization. Techniques have also progressed to include multiple needle sizes and types, such as Franseen-tip and fork-tip needles, for improved outcomes.<br /><br />Factors that contribute to increasing the diagnostic yield of EUS/FNA include the target lesion, endoscopist skill, needle size, FNA technique, rapid onsite cytopathology evaluation (ROSE), and cytologist expertise. Needle placement and movement are also important, with the edge of the lesion being preferred for better results.<br /><br />The choice of needle size (25 or 22 gauge) depends on factors such as lesion characteristics and ease of use. The use of a stylet during the procedure is not recommended. Suction during EUS-TA can improve cellularity and diagnostic yield, but it may also increase bloodiness.<br /><br />The number of passes required for a diagnosis varies depending on the target, with pancreatic masses typically requiring more passes than lymph nodes. ROSE can provide immediate assessment of material adequacy, allowing for adjustments in the EUS-TA strategy if needed.<br /><br />EUS-guided fine needle biopsy (FNB) has shown superior results compared to fine needle aspiration (FNA) in terms of histologic yield and cancer diagnosis. Different types of FNB needles, such as Franseen-tip and fork-tip, have demonstrated high diagnostic accuracy regardless of the use of suction or stylet retraction.<br /><br />EUS-TA techniques have also been applied to liver biopsies, with fork-tip and Franseen-tip needles outperforming other FNB needles.<br /><br />Overall, EUS-TA techniques continue to evolve, with the potential for future applications in precision medicine, such as next-generation sequencing and the creation of tumor organoids. However, there are still challenges and risks associated with EUS-TA, including complications such as pancreatitis and intra-cyst bleeding.

Keywords

EUS-guided tissue acquisition

EUS-TA techniques

EUS fine needle aspiration

EUS fine needle biopsy

specimen adequacy

diagnostic yield

accuracy rate

adverse event rate

pancreatic EUS-TA

quality indicators