Endoscopic Ultrasound-guided Sampling of Solid Pancreatic Lesions: A Comparative Analysis of 25 Gauge Versus 22 Gauge Core Biopsy Needles

Abstract

Background: Pancreatic mass sampling has historically been performed by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). However, its sensitivity has been reported to be within a wide range, which limits its reliability. Fine needle biopsy (FNB) has been shown to have superior diagnostic performance and is increasingly replacing fine needle aspiration. In FNA, 25 gauge (G) needles appear to outperform 22G. Data comparing these sizes in FNB platforms is limited. We aimed to prospectively compare the performance of 22G and 25G Franseen-tip core biopsy needles in the sampling of solid pancreatic lesions. Patients and Methods: Patients who underwent EUS-FNB of pancreatic lesions at the Indiana University Hospital using 2 needle sizes: 25G (Study group) and 22G (Control group) using the Acquire needle (Boston Scientific Co., Natick, MA, USA) were enrolled. Needle choice was left to the discretion of the endosonographer. Tissue specimens were evaluated onsite, and underwent touch and smear and cellblock preparation. Specimens were independently evaluated by 2 expert cytopathologists blinded to diagnosis. Cytopathologists assessed cytological yield (on smears) and histological yield (on cellblock) using a validated scoring system reached by a consensus among our cytopathologists as we have previously published. Results: A total of 75 patients (42 males, median=65 years) underwent EUS-FNB during the study period (2017-2018): 50 using 25G and 25 using 22G needle. Diagnostic yield was numerically higher in 25G (98% vs. 88%, p=0.105). Number of passes for smears were similar, however the 25G group required additional passes for cell-block (1.6 vs. 0.4, p=0.001). 25G was used more frequently for pancreatic head and uncinate process sampling (70% vs. 52%, p=0.126). Four patients had self-limited adverse events in the 22G group, but none in the 25G group. Conclusion: We report no difference in the diagnostic yield between 25G FNB vs. 22G sampling device with Franseen style tip, however, the 25G needle use was associated with the need of additional passes to collect a sufficient cell block.