P288 Diagnostic yield of biliary brush cytology in a teaching secondary care hospital: a single-centre study

Abstract

<h3>Introduction</h3> Biliary brush cytology obtained during endoscopic retrograde cholangiopancreatography (ERCP) is a primary diagnostic tool in the assessment of biliary strictures. Reported sensitivity ranges from 6-64% with a consistently high specificity. The aim of this study was to assess the diagnostic yield of brush cytology in the evaluation of biliary strictures in a teaching hospital setting. <h3>Methods</h3> We conducted a retrospective review of all patients who had brush cytology obtained during ERCP from January 2017-December 2021. The procedures were performed by three independent operators. Data collected included cross-sectional imaging, liver biochemistry, tumour markers and histopathology results. Brush cytology, histology obtained by alternative means including endoscopic ultrasound guided fine needle biopsy (EUS-FNB) or radiologically-guided biopsy and outcomes from regional pancreaticobiliary multi-disciplinary team were collected to confirm the final diagnosis. <h3>Results</h3> 122 brush cytology samples were sent. 15 repeat samples and 7 with incomplete data were excluded. 100 subjects were included for the final analysis. (male=57, mean age=69 years). True negative Sensitivity, specificity, positive-predictive value (PPV) and negative-predictive value (NPV) were 27.45%, 100%, 100% and 59.97%, respectively. Indeterminate results were classed as false negatives. All patients with indeterminate cytology had a final diagnosis of malignancy. Patients with suspected malignancy and negative cytology were referred for alternative means of obtaining tissue diagnosis, predominantly via EUS-FNB. Malignant diagnoses were mainly pancreatic cancer (52.9%), and cholangiocarcinoma (CCA, 39.2%). Brush cytology had a 22.2% and 40% sensitivity for pancreatic cancer and CCA, respectively. <h3>Conclusions</h3> Our single-centre data confirms the high specificity of brush cytology, although our sensitivity and NPV are in the lower end of the range of the current literature. In a non-tertiary centre where EUS is not available, enhancing the diagnostic sensitivity of brush cytology could prevent delays in diagnosis. Roth <i>et al</i><i>.</i> found that bile aspiration before and after conducting brushing improved their sensitivity from 66.7% to 84.3%. This technique has been discussed in our department and will be implemented alongside brush cytology. We will review the impact it has on diagnostic yield in one year. <h3>Reference</h3> Roth GS, Bichard P, Fior-Gozlan M, et al. Performance of bile aspiration plus brushing to diagnose malignant biliary strictures during endoscopic retrograde cholangiopancreatography. <i>Endosc Int Open</i>. 2016;4(9):E997-E1003. doi:10.1055/s-0042-108854