Randomized trial comparing the 25G and 22G Franseen needles in endoscopic ultrasound-guided tissue acquisition from solid pancreatic masses for adequate histological assessment

Background: The effects of the Franseen needle size in endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) of solid pancreatic masses remain unclear. This study aimed to compare 25G and 22G Franseen needles in terms of adequate tissue acquisition from solid pancreatic masses. Methods: In this single-center, crossover, randomized noninferiority trial, eligible patients underwent EUS-FNB with both 25G and 22G Franseen needles in a randomized order between November 2018 and August 2020. Tissue specimens from each pass were separately evaluated based on the cellularity scoring system. The primary outcome was the proportion of acquired specimens allowing adequate histological assessment (cellularity score ≥3). A –15% noninferiority margin was assumed. Results: Data from 88 patients were analyzed, which showed malignant and benign lesions in 84 (95.5%) and four (4.5%) patients, respectively. Of the 88 specimens, 62 (70.5%) and 69 (78.4%) acquired using 25G and 22G needles, respectively, allowed adequate histological assessment. The adjusted proportion difference was –6.6% (95% confidence interval –8.8% to –4.5%), indicating noninferiority of the 25G Franseen needle (P < 0.001). The diagnostic accuracies of the 25G and 22G needles were 86.4% and 89.8%, respectively, with no significant difference (P = 0.180). Adverse events occurred in one patient. Conclusions: The 25G Franseen needle showed a noninferior adequate tissue acquisition and similar diagnostic performance compared to that of the 22G Franseen needle. However, a 15% noninferiority margin was high for clinical use; thus, further consideration is needed (Clinical Trial Registry no. UMIN000034596).