EUS-guided tissue acquisition: an evidence-based approach (with videos)

safe and accurate and achieve a high diagnostic yield. The key relevant outcomes of EUS-TA include specimen adequacy, diagnostic yield, accuracy, and adverse events. There are several limitations and technical challenges associated with this procedure. Low diagnostic yield (false-negative diagnosis) is the most important pitfall, with the potential to negatively impact patient outcomes by inappropriate patient care. A recent review reported a falsenegative diagnoses rate of 4% to 45% in solid pancreatic masses, 21% to 53% in pancreatic cystic neoplasms, and 6% to 14% in lymph nodes. 3 This usually is as a result of sampling errors (related to improper EUS-TA, errors in image recognition, experience of the endosonographer, and lesion characteristics). 3-5 Several variables have been studied to optimize outcomes associated with EUS-TA. These include performance of EUS-FNA versus FNB, needle gauge, use of a stylet and suction, number of passes, sampling technique, presence of an on-site cytopathology evaluation (OCE) during the procedure, and the skill and experience of the endosonographer and the cytopathologist. The aims of this technical review were as follows: (1) perform a systematic review of variables that impact outcomes (diagnostic yield/accuracy and adverse events) related to EUS-TA and (2) provide evidence-based recommendations regarding techniques related to EUS-TA.