Sa1405 A Prospective Randomized Trial Comparing the 22-Gauge Needle With and Without a Side Port for Endoscopic Ultrasound Fine Needle Aspiration of Solid Pancreatic Mass Lesions Hirotoshi Ishiwatari*, Tsuyoshi Hayashi, Hiroshi Kawakami, Hiroyuki Isayama, Takao Itoi, Hiroyuki Hisai, Michihiro Ono, Yoko Abe, Natsuyo Yamamoto, Fumihide Itokawa, Tadashi Hasegawa Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Sapporo, Japan; Department of Gastroenterology and Hepatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan; Department of Gastroenterology, The University of Tokyo, Tokyo, Japan; Department of Gastroenterology and Hepatology, Tokyo Medical University, Tokyo, Japan; Department of Gastroenterology, Japanese Red Cross Date General hospital, Date, Japan; Department of Surgical Pathology, Sapporo Medical University School of Medicine, Sapporo, Japan Background: Endoscopic ultrasound fine needle aspiration (EUS-FNA) is widely used for obtaining specimens from pancreatic mass lesions, owing to its high diagnostic accuracy, safety, and low invasiveness. However, it remains imperfect and needs modification to enable accurate diagnosis. The 22-gauge (G) fine needle aspiration (FNA) needle is widely used owing to its maneuverability. However, a 19G needle is superior in terms of tissue acquisition. To overcome this limitation, 22G FNA needles with a lateral side port have been developed. The side ports initially had a reverse beveled edge. Recently, needles with a round side port have been developed, which may reduce tissue damage and blood contamination, and improve diagnostic yield. Preliminary results have shown high diagnostic accuracy. We compared 22G FNA needles with and without a side port in pancreatic mass lesions in a multicenter prospective randomized control trial. Patients and Method: Between January and September 2013, consecutive 160 patients with a suspected solid pancreatic mass in five tertiary referral centers were enrolled. Patients were randomized to 22G FNA needle (EZ Shot 2, Olympus Medical Systems) with and without a side port groups (with and without groups, respectively). The primary endpoint was diagnostic accuracy. The secondary endpoints were adequacy of tissue acquisition and quality of the histological specimen (degree of contamination and amount of blood). Evaluations were made using a scoring system, by experienced attending pathologists, who were blinded to the clinical information, including the needle type. Results: Analysis of 158 patients (79 per group) was performed. Two patients did not undergo EUS-FNA after allocation. In four patients (three in the with group and one in the without group), EUS-FNA failed owing to difficulty of the puncture. There was no significant difference in the diagnostic accuracy rate (with group, 92.4% (73/79) vs. without group, 86.1% (68/79); P Z 0.3, Fisher’s exact test). In subgroup analysis, trainees (endosonographers with experience of fewer than 40 EUS-FNAs) had diagnostic accuracy rates of 97.4% (37/38) and 81.4% (35/43) in the with and without groups, respectively (P Z 0.03, Fisher’s exact test). Adequate samples for histological diagnosis were obtained in 61.3% (47/76) and 44.2% (34/78) of patients from the with and without groups, respectively (P Z 0.03, Fisher’s exact test). No significant difference was seen in the degree of sample contamination and amount of blood between the groups. Conclusion: There was no significant difference in diagnostic accuracy between the needle types. However, the needle with a side port allowed trainees to obtain the correct diagnosis at a higher rate. Moreover, the needle with a side port is superior for tissue acquisition.(Clinical trial registration number: UMI08120)