Slow-pull technique yields better quality smears: prospective comparison of slow-pull and standard suction techniques of endoscopic ultrasound-guided fine-needle aspiration

Abstract

Background Diagnostic accuracy and quality of smears obtained by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) are influenced by characteristics of suction and examined organ. Aims and methods Efficiency of EUS-FNA and quality of smears obtained by slow-pull (SP) and standard suction (SS) techniques was prospectively compared in the sampling of pancreatic (N = 56) and extrapancreatic (N = 145) tumors. Results SS technique resulted in a higher number of smear pairs both in pancreatic (1.74 vs. 3.19; p < 0.001) and extrapancreatic tumors (1.62 vs. 3.28; p < 0.001); however, it decreased the proportion of diagnostic smears (46.69% vs. 36.52%; p = 0.002 and 49.17% vs. 30.67%; p < 0.001) and increased the bloodiness (1.51 vs. 2.07; p < 0.001 and 1.48 vs. 2.05; p < 0.001). In pancreatic cancers, no difference was observed in terms of diagnostic accuracy (81.38% vs. 83.45%) and cellularity (1.44 vs. 1.27; p = 0.067); however, they were substantially higher in extrapancreatic tumors using SP technique (71.41% vs. 60.71% and 1.34 vs. 0.77; p < 0.001). Only SP technique resulted in a significant difference between examiners in terms of technical success rate and quality of smears without any decrease of diagnostic accuracy. Conclusions SP technique yields better quality smears independently from tumors characteristics; however, it shows significant examiner-dependency. SS technique reduces the diagnostic accuracy of sampling in extrapancreatic tumors.