PTH-041 Prospective study of the diagnostic yield from 20g FNB needle in routine upper GI and HPB lesions

Introduction Improvements in the EUS FNA and FNB needle design and optimisation of tissue acquisition techniques have resulted in better diagnostic yield (DY). In addition, recently there has been considerable interest in histological processing of tissue acquired using newer ‘core’ FNA needles. At BSG 2016 we provided preliminary data on DY of tissue acquired using standard FNA needle. We hereby present data on yield of 20G Cook EchoTip Procore TM FNB needle. Aim To compare the diagnostic yield of 20G FNB needle and compare the incremental yield of histological over cytological preparation of tissue acquired. Methodology Prospective non-blinded randomised study. All patients undergoing EUS guided FNA/FNB from January 2016 to January 2018, for all upper GI and HPB lesions were included. FNB was performed using Cook Echotip Procore 20GTM needle, Olympus EU-ME2TM processor and linear echoendoscopes was used. All patients had 2 or 4 passes done with the same needle, specimens from each pass were randomly collected in BD Cytorich TM or Formalin. Each preservative had either 1 or 2 passes of material. Only C5 malignancy diagnosis from the primary pathologist or from second expert opinion with MDT acceptance was considered positive for cancer, other non-malignant conditions was considered as positive for statistical purposes only when clear diagnosis was offered by pathologist. Results In total, 147 patients had EUS guided sampling and 111 patients had EUS FNB with 20G FNB needle. 68 M: 43 F. Average age was 66.7 years (±11.3). Of these, 102 had samples both for cytology and histology. Final diagnosis was made in 92 (90.2%) patients. Pancreatic cancer was seen in 52 (51%) patients, cholangiocarcinoma in 7 (6.7%), NET/GIST in 11 (10.8%), Lymphoma in 11 (10.8%), malignant nodes in 6 (5.9%), other cancers (e.g. rhabdomyosarcoma) in 6 (5.9%), benign (e.g. chronic pancreatitis, autoimmune pancreatitis, paraganglioma, reactive nodes etc) in 8 (7.7%), and no diagnosis was made in 10 (9.8%). Histological processing provided answers in 87 (78.3%) patients with combined cytological and histological processing providing diagnosis in the rest of 15 (13.5%) with overall diagnostic yield of 91.9% (102 patients). Conclusion Our study results show that adequate samples can be obtained for histological processing with Cooke Procore TM FNB needles with good cumulative diagnostic yield (92%) and significant diagnostic yield from preferentially processing samples for histological assessment rather than standard cytology, possibly due to better preservation of tissue architecture and cell morphology. Limitations include non-specialist reporting cytopathologist and non-randomised retrospective design.