Mo1284 HIGH HISTPATHOLOGICAL ACCURACY OF EUS-FNA FOR SOLID PANCREATIC MASSES BY USING 20G FORWARD BEVEL CORE BIOPSY NEEDLE. RESULT OF A PROSPECTIVE STUDY

EUS-FNA is the standard method for pathological diagnosis of pancreatic mass lesion. A new 20G core biopsy needle with a forward bevel has been developed instead of a reverse bevel. We conducted the present study to evaluate the histological diagnostic performance and yield for acquisition from solid pancreatic mass of this novel FNB needle with forward bevel (UMIN000025738). This was a prospective study at single center. Consecutive patients with a solid pancreatic mass larger than 15mm which required EUS-FNA for pathological confirmation were enrolled between February and October 2017. EUS-FNA was performed with a 20G ProCore needle (Cook Endoscopy, NC, USA) and the FNA procedure was repeated until the obtained specimen was considered adequate by rapid on-site cytopathological evaluation. The final diagnosis was determined by the combination of histopathological and clinical findings. The primary endpoint of this study was the accuracy of histopathological diagnosis. The secondary endpoints were 1) the technical success rate, 2) the sample adequacy for histopathology, 3) the accuracy of cytopathological diagnosis and 4) the complication rate. We assumed be the null hypothesis which is 0.77 and the alternative hypothesis which is 0.9 for the primary endopoint. The minimum sample size was 60 patients to grantee the statistical power of 0.80 to use exact binomial test with a two-sided type I error of 0.05. However, we allowed up to 70 patients to be enrolled as we would have expected some non-evaluable cases. The final diagnosis were pancreatic cancer in 65 patients, neuroendocrine neoplasm, malignant lymphoma, and mass forming chronic pancreatitis in each one patient, and autoimmune pancreatitis in 2 patients, respectively. The lesion was located in the head of the pancreas in 21 (30%) and punctured from duodenum in 19 (27%). The puncture was successful in all cases and the obtained samples were evaluable for histopathological examination in all cases. The histopathological sensitivity and specificity was 0.91 and 1.00, respectively, and the primary endpoint of overall accuracy was 0.929 and the estimated 95% confidence interval was [0.841-0.976] which does not include 0.77. The sensitivity, specificity, and overall accuracy of cytological examination was 0.96, 1.00, and 0.96, respectively. There were no severe complications. In this first single center prospective study, the new 20G core biopsy needle with a forward bevel afforded superior histopathological diagnostic performance and it will become a standard puncture needle for pancreatic mass.