Is It Time to Take a Pass on the Increased Number of Passes in EUS-FNA?

Abstract

Despite the extensive use of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), there still exists a wide variation in the number of samples required to ensure acquisition of diagnostic material from pancreatic lesions. Although multiple passes can be performed during EUSFNA, prolonging the procedure likely increases risk, decreases procedural efficiency, and increases the probability of samples being tainted with blood. It has been 21 years since EUS-FNA was used to obtain pancreatic tissue for cytologic analysis [1, 2], 16 years since the publication of the first reports evaluating the clinical impact and staging of pancreatic lesions sampled by EUSFNA [3], and 14 years since the publication of the initial reports of the evaluation of the number of passes needed to obtain a diagnostic yield and the significance of on-site cytopathology during the procedure [4–7]. During this time, the focus has been on determining the necessity of on-site cytopathologic evaluation, the optimal number of needle passes, and the most effective needle type used for tissue acquisition. Despite numerous studies addressing these issues, many endoscopists are still perplexed about the nature of the best practices needed to ensure optimal results, in particular with regard to the need for on-site cytopathology for skilled and experienced endosonographers practicing at a high-volume center. To date, multiple meta-analyses have confirmed the diagnostic accuracy, cost-effectiveness, accuracy, and safety of EUS-FNA for solid pancreatic lesions [8–12]. Moreover, structured literature reviews have concluded that rapid on-site evaluation (ROSE) improves diagnostic accuracy [8, 9]. Notwithstanding these considerable successes, ongoing refinements to EUS-FNA continue to be explored. Regardless of the likelihood that increasing numbers of passes raises the risk of needle failure, tissue injury, postprocedural complications, and medical expenses, the endosonographer is caught between the need to provide adequate tissue needed to optimize diagnostic yield weighed against the cost and risk of making additional passes. Failed EUS-FNA often engenders additional risk and expense due to the need to repeat EUS or to obtain tissue with radiologic or surgical guidance. Moreover, as treatment options for pancreatic cancer advance, rendering an onsite diagnosis alone may not be adequate, since additional tissue may be required to perform ancillary studies and molecular mapping. Nevertheless, ROSE may not be financially viable due to excess time commitment, limited resources, relatively low reimbursements, and acceptable adequacy rates achieved by more experienced endosonographers. In order to have a sustainable EUS practice with optimal clinical outcomes, it may be beneficial to provide some degree of ROSE training for endosonographers incorporating the ‘‘fanning’’ FNA technique combined with an algorithmic approach to needle selection [13–15]. In this issue of Digestive Diseases and Sciences, Schmidt et al. [16] examined current practices of lesion sampling, weighing diagnostic accuracy against the probability of adverse events in the presence and absence of ROSE. The authors provide empirical data regarding the diagnostic yield and performance characteristics of EUS-FNA of solid pancreatic lesions using mathematical modeling to determine the likelihood of adverse events with a fixed number of passes (no-ROSE) versus a variable number of passes (ROSE) while controlling for other variables. Schmidt and colleagues used a discrete-event simulation model to conclude that ROSE reduces the number of passes, thereby reducing the S. Hebert-Magee R. H. Hawes S. Varadarajulu (&) Center for Interventional Endoscopy, Florida Hospital, 601 East Rollins Street, Orlando, FL 32803, USA e-mail: svaradarajulu@yahoo.com