Clinical utility of stent cytology for the diagnosis of pancreaticobiliary neoplasms.

Abstract

ERCP is frequently the technique of choice for the diagnosis and palliative treatment of pancreaticobiliary neoplasms. The sensitivity of tissue sampling techniques has been disappointing. Two small series have reported a high diagnostic yield from cytological examination of cellular debris from removed biliary stents. The aim of this study was to determine the clinical utility of stent cytology for the diagnosis of biliary and pancreatic neoplasia. Patients who had biliary or pancreatic stents removed at ERCP and evaluated cytologically were the subjects of this study. Stents were scraped and washed, and the cellular debris was examined cytologically and recorded as positive, atypical, or negative. Patient demographics, ductal stricture, and stent characteristics were recorded. Between January, 1994 and January, 2001 a total of 126 biliary stents from 101 patients (61 male, 40 female, mean age 62 yr) and 29 pancreatic stents from 19 patients (seven male, 12 female, mean age 58 yr) were examined. The sensitivity, specificity, positive predictive value, and negative predictive value of biliary and pancreatic stents for the diagnosis of neoplasia were: 11%, 100%, 100%, 53%, and 25%, 100%, 100%, 77.8%, respectively. The sensitivity improved slightly if all degrees of atypia were considered positive for neoplasia. The mean duration of stent placement was 93.6 days for biliary stents and 43.5 days for pancreatic stents. Biliary and pancreatic stent cytology has limited clinical utility in the diagnosis of pancreaticobiliary neoplasia, owing to poor sensitivity. In addition, the time lag between stent placement and removal for cytologic examination further limits its contribution to patient management.