19 G nitinol needle versus 22 G needle for transduodenal endoscopic ultrasound-guided sampling of pancreatic solid masses: a randomized study

Background The aim of this prospective multicenter study was to compare a flexible 19 G needle with nitinol shaft (19 G Flex) with a standard 22 G needle for transduodenal endoscopic ultrasound (EUS)-guided sampling of pancreatic head tumors. Methods Patients with pancreatic head tumors requiring tissue diagnosis were randomized into two arms: puncture with either a 19 G Flex needle or a 22 G needle. The primary end point was diagnostic accuracy for malignancy. The secondary end points were ergonomic scores, sample cytohistological quality, and complications. A 6-month follow-up was performed. Results 125 patients were randomized and 122 were analyzed: 59 patients in the 19 G Flex arm and 63 patients in the 22 G arm. The final diagnosis was malignancy in 111 patients and benign condition in 11. In intention-to-treat analysis, the diagnostic accuracy for malignancy of the 19 G Flex and 22 G needles was 69.5% (95% confidence interval [CI] 56.1%-80.8%) vs. 87.3% (95%CI 76.5%-94.4%), respectively ( P =0.02). In per-protocol analysis excluding eight technical failures in the 19 G Flex group, the diagnostic accuracy of the 19 G Flex and 22 G needles was not statistically different: 80.4% (95%CI 66.9%-90.2%) vs. 87.3% (95%CI 76.5%-94.4%; P =0.12). Technical success was higher in the 22 G arm than in the 19 G Flex arm: 100% (95%CI 94.3%-100%) vs. 86.4% (95%CI 75.0%-94.0%), respectively ( P =0.003). Transduodenal EUS-guided sampling was more difficult with the 19 G Flex (odds ratio 0.68, 95%CI 0.47-0.97). Conclusion The 19 G Flex needle was inferior to a standard 22 G needle in diagnosing pancreatic head cancer and more difficult to use in the transduodenal approach.