PTU-044 Improved Diagnostic Yield with Cell Block Only Preparation of EUS Guided FNA Specimens

Abstract

<h3>Introduction</h3> Recently increased attention has been paid to the post FNA processing of specimen including on site smear preparation or extruding the entire specimen into preservative for cytotechnician assisted cell block or smear preparation, to improve diagnostic yield (DY). Due to logistical and cost issues, many centres like ours, do not have rapid onsite smear evaluation facilities. <h3>Aim</h3> Comparative analysis of cell block only versus cell block and smear preparation of specimens acquired via standard EUS guided FNA technique. Secondary outcomes include assessment of cellularity of the specimens. <h3>Methods</h3> Retrospective case-note review study. Consecutive samples were evaluated from January 2010 to October 2015 at our institution. All FNA procedures involving solid lesions were included. Choice of needle was up to the discretion of the endosonographer. All specimens were fully extruded with saline/stylet into ‘Cytorich’^TM containers, cytotechnician randomly decided regarding smear and cell block or cell block only preparation. Cellularity was graded simply as adequate or inadequate. <h3>Results</h3> 118 samples were collected from 112 patients, 69 male/43 female patients, and mean age of 64.1 ±9.6 years. Initial 49 FNAs were performed using Aloka alpha5 Olympus^TM processor, rest with EU-ME2 Olympus^TM processor. All the procedures were done by 4 experienced endosonographers and two trainees, following stadard technique. Average 3.89 ±0.47 passes, 5–20 mls of suction, stylet used only in the first pass. 40 samples were obtained with 19 G needles, 46 samples with 22 G, 7 samples with 25 G and 23 obtained using combination/core needles. 59 Solid pancreatic lesions, rest of them included lesions in the wall, lymph nodes, liver, pericardial, retroperitoneal etc. 33 cell block only (CB) and 85 smear plus cell block (SCB) were done. Greater number of CB samples (29/33, 87.8%) had adequate cellularity compared to SCB (68/85, 75.2%), ‘p’ value =0.059, cytological diagnosis was made more often with CB (29/33, 87.8%) compared to SCB (64/85), p = 0.071. No statistical significance was seen in univariate or multivariate logistic regression analysis for tumour size(≥2 cm), route of FNA (transoesophageal, transgastric or transduodenal) or size of needle (19 G, 22 G or 25 G). <h3>Conclusion</h3> Our study shows better diagnostic yield when the entire specimen was processed exclusively as cell block only rather than split into smear initially and remnant tissue for cell block preparation. Cell block alone preparation also preserves more material for immunohistochemistry and more advanced DNA analysis techniques. Limitations include the retrospective nature of study, variable operator and cytopathologist experience and ever improving FNA techniques (use of elastography, newer EUS processor). <h3>Disclosure of Interest</h3> None Declared