Factors Affecting the Yield of Brush Cytology for the Diagnosis of Pancreatic and Biliary Cancers

Abstract

Pancreatobiliary malignancies often present as biliary strictures. Biliary brush cytology is an established diagnostic technique in the investigation of such strictures. The main shortcoming of the test, however, is its low sensitivity. The aim of this was to identify factors associated with a positive yield on biliary brush cytology. Consecutive patients who had brush cytology for investigation of biliary strictures from 2005 to 2007 were included. Association of several factors with a positive result on brush cytology was studied using univariable and multivariable logistic regression analyses. Two hundred eighty patients were evaluated. One hundred nineteen (42.5%) patients had a final diagnosis of malignancy; of whom, 55 had a positive brush cytology (sensitivity, 46%; specificity, 100%). On multivariable analysis, age (odds ratio [OR], 1.2; 95% confidence interval [CI], 1.06-10.4 per 5-year increase), total serum bilirubin levels (OR, 1.3; 95% CI, 1.01-1.6 per 5-unit increase), and presence of a mass on cross-sectional imaging (OR, 11.7; 95% CI 5.1-27.2) were independent predictors of a positive brush cytology result. Increasing age, higher serum bilirubin levels, and presence of a mass on cross-sectional imaging are independent factors associated with a positive result on biliary brush cytology. These findings suggest use of complementary tissue acquisition techniques in selected cases.