4544 Prospective comparison of 22 gauge versus 19 gauge needle for endoscopic ultrasound directed fine needle aspiration of pancreatic masses: does size matter?

Abstract

Background: EUS guided FNA allows for accurate diagnosis of pancreatic neoplasms. Yield is hampered by the small amount of tissue obtained with a standard 22 gauge needle. Larger needles may improve diagnosis but may also increase risks. Methods: We prospectively analyzed all patients referred with pancreatic masses over six months. After staging with radial EUS (Olympus GF-UM20), real-time FNA was attempted using curved linear array EUS (Olympus GF-UC30P) with a 22 gauge needle (Wilson Cook EchoTip®) and a 19 gauge needle, (Mediglobe). The order of use was alternated. Smears and cell blocks of aspirates were made immediately and sent for interpretation. Diagnosis was confirmed at surgery, by additional core biopsies or by clinical course. Cytologic diagnosis, needle characteristics and complications were recorded and aspirates blindly reviewed for relative quantity and quality of cellular material. Results: Over six months, 22 patients were referred for EUS of a pancreatic mass. Of these, 20 underwent FNA, 6 with 22 g alone, 1 with 19 g alone and 14 with both, (attempt failed with the stiffer 19g needle in 2 additional cases). 14 of these cases eventually were proven to be cancers. Other diagnoses included one CIS, 2 chronic pancreatitis, 3 cysts or pseudocysts. Average total needle passes per case was 2.7, divided equally between types. 22 g detected 10 of 13 cancers, (77% sens.) with 100% specificity. 19 g detected 8 of 9 cancers (89% sens.) with 100% specificity, when tissue was obtained. Overall sensitivity was 82%. Accuracy with 22 g needle was 79% and 93% with 19 g needle, for an overall accuracy of 85%. Of eight cancers sampled with both needles, three 19 g aspirates were felt to be of better quality, due to increased tissue sampling, preservation of architecture and greater cellularity. Three 22 g. aspirates were felt to be superior due to less blood and better cellularity. Two samples were identical. In several cases, cell blocks of spun aspirates from both needles increased yield. One case of minor bleeding was linked to use of a 19 g needle. In no case was cancer detected with one needle and not the other. Conclusion: 1). Both 19 g and 22 g needles are useful for EUS guided FNA of pancreatic masses. 2). Needle size does not clearly correlate with specimen size or quality. 3). 19 gauge needles were more difficult to place, especially from the duodenum and may be associated with a higher risk of bleeding. 4). Cell blocks of aspirates probably increase diagnostic yield.