ASGE Therapeutic EUS for Advanced Endosonographers (On-Demand) | September 2022-1 Savides

1 Savides_EUS Guided Tissue Acquisition
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This document discusses advances in EUS-Guided Tissue Acquisition (EUS-TA) for diagnostic purposes. The ideal techniques for EUS-TA include high specimen adequacy, high diagnostic yield, high accuracy rate, low adverse event rate, and minimal number of passes. Quality indicators for pancreatic EUS-TA include achieving a diagnostic rate of adequate samples, high sensitivity and diagnostic rate for malignancy, and low incidence of adverse events.<br /><br />The goals of EUS-TA have evolved from simply obtaining a cytologic diagnosis to obtaining pathologic diagnosis and material for molecular and genetic characterization. Factors that influence the diagnostic yield of EUS/FNA include the target lesion, endoscopist skill, needle size, FNA technique, and cytopathology evaluation. Needle placement and movement should focus on the edge of the lesion, and aggressive, swift movements are more effective.<br /><br />The choice of needle size for EUS FNA, whether 25g or 22g, depends on the target lesion and the endoscopist's preference, with some studies suggesting that 25g needles have increased sensitivity. The use of a stylet during the procedure does not significantly affect the diagnostic yield. Suction during EUS-FNA can increase cellularity and diagnostic yield but also increases bloodiness.<br /><br />Comparisons between EUS FNA and EUS FNB, which involves cutting tissue for core samples, show that EUS FNB outperforms EUS FNA in terms of histologic yield and cancer diagnosis. The choice of the FNB needle type, such as Franseen and Fork-tip, can affect diagnostic accuracy.<br /><br />Rapid On-site Pathologic Evaluation (ROSE) allows for immediate assessment of samples and can impact diagnostic certainty and therapeutic decisions. EUS FNB can also be used for ROSE by employing touch imprint cytology (TIC) on the cores.<br /><br />Future uses of EUS-TA include NGS, RNA sequencing, microRNA sequencing, and creating tumor organoids for precision medicine.<br /><br />Challenges in EUS FNA of pancreatic cysts include the need to change management approaches and the risk of complications. Through-the-needle-biopsy (TTNB) and EUS FNB for liver biopsies are alternative techniques with their own limitations and risks.<br /><br />In conclusion, EUS-FNB has shown advantages over EUS-FNA in terms of diagnostic yield, histologic material, and potential for molecular profiling. Franseen and Fork-tip needles are recommended for EUS FNB, and the use of TIC can achieve comparable results to EUS FNA ROSE. However, further research is needed to fully understand the benefits of EUS FNB for molecular profiling tissue.
Keywords
EUS-Guided Tissue Acquisition
diagnostic yield
needle size
cytopathology evaluation
EUS FNB
histologic yield
Franseen
Fork-tip
ROSE
molecular profiling