Increased accuracy of FNA-based cytological diagnosis of pancreatic lesions by use of an ethanol-based fixative system: A STROBE compliant study

Abstract

EUS-guided fine needle aspiration cytology (FNA) is the gold standard of evaluation of solid pancreatic lesions. However, accuracy is generally low. The aim of this study was to compare the diagnostic yield of conventional cytology (CC) with liquid-based cytological analysis using an ethanol based fixative system (LBC) without onsite cytopathological assessment. We performed a retrospective evaluation in patients referred to the Department of Interdisciplinary Endoscopy at Jena University Hospital for FNA of pancreatic masses between 2008 and 2015. LBC preservation of specimen was introduced in April 2011. Gold standard was defined as a surgically obtained histology or a patient follow-up of at least 1 year for diagnosis or exclusion of malignancy. 172 patients were included into the final analysis. Mean age was 64.8 years (SD 12.4 years), 105 patients were male. 107 lesions were malignant, while 65 lesions were benign. 89 specimens were evaluated by CC, whereas 83 specimens were processed by LBC. Liquid-based cytology performed significantly better than conventional cytology in terms of sensitivity (87.8% vs 67.2% (P = .021)), specificity (100% vs 87.1% (P = .047)) negative predictive value (NPV) (85% vs 58.7% (P = .009)) and accuracy (92.8% vs 74.2% (P = .001)). We observed no learning curve after implementation of LBC Liquid based cytology is a simple and inexpensive technique that helps improving sensitivity, specificity, NPV and accuracy over conventional cytology in fine needle aspirates from patients with pancreatic lesions. Therefore, this real-world evidence shows, that EUS-FNA specimen processing should be performed using LBC to achieve best possible results.