Su1399 How Many Needling Should We Perform Using 25-Gauge Needle to Obtain Sufficient Specimens in EUS-FNA for Pancreatic Mass? A Prospective Study

In an earlier past study, 7 or more passes were recommended using EUS-FNA for pancreatic mass lesion without on-site cytology. Some facilities where on-site cytology was not available have followed this recommendation, but feasibility of this recommendation should be re-evaluated considering the advancement of EUS-FNA technique and devices. Recently, a 25-gauge needle is considered feasible for use with EUS-FNA of pancreatic mass lesions because of its safeness and better operability. We prospectively evaluated how many passes we should puncture with 25 G needle before obtaining a sufficient specimen. During Apr. 2009 and Apr. 2010, 22 consecutive patients with pancreatic mass lesions were enrolled in this study. Using both Cyto-QuickTM stain and Papanicolaou stain, cytoscreeners and pathologists advised us when we could obtain the specimens. Cyto-QuickTM stain was used for rapid on-site cytology and Papanicolaou stain was used for final diagnoses in the laboratory. We performed EUS-FNA using typical methods and finished it when rapid on-site cytology indicated that a sufficient specimen had been obtained. The numbers of passes (mean±SD) were 2.72±1.31 in Cyto-Quick stain and 1.71±1.16 in Papanicolaou stain. In Papanicolaou stain, sampling rate was 63.6 % at first pass, 77.2% at second pass, 86.2% at third pass and 95.4% at forth pass. In all cases, samples were obtained within 5 passes. Final diagnosis were 15 cases of adenocarcinoma, 3 cases of endocrine cell tumor, and 4 cases of tumor forming pancreatitis. The respective sampling rate, sensitivity, specificity and accuracy of these cases were 100%, 100%, 100% and 100%. Our study showed that 4 or 5 passes were sufficient to obtain sufficient specimens for pancreatic mass lesions in EUS-FNA using 25-gauge needle.