Endoscopic brush cytology from the biliary duct system is still valuable

Abstract

Introduction: The aim of this study was to define sensitivity, specificity and positive and negative predictive values of endoscopic retrograde cholangiopancreatography (ERCP) brush cytology from biliary strictures obtained over a period of 12 years in a county hospital in Denmark.

Material and methods: Patients with cytology specimens identified by brushings of the bile duct, pancreatic duct and ampulla of Vater were included. The specimens were reported as unsatisfactory, normal, atypical, suspicious for malignancy or malignant. Our evaluation comprised 75 specimens. For the statistical analysis, an atypical cytology result was considered benign, and a suspicious result was considered malignant. The cytological diagnoses were compared with the final diagnoses which were established either by histopathology (surgery, biopsy or autopsy) or by at least one year of clinical follow-up.

Results: Of the 75 specimens included, 40 were diagnosed as cytologically benign (35 normal and five atypical) and 35 as cytologically malignant (22 suspicious for malignancy and 13 malignant). Comparing the cytological diagnosis with the final diagnosis, we found 35 to be true positives, 22 to be true negatives, zero to be false positives and 18 to be false negatives. Of the five atypical specimens, four were false negatives. The operating characteristics were: 66% sensitivity, 100% specificity, 100% positive predictive value and 55% negative predictive value. The diagnostic accuracy was 76%.

Conclusion: Suspicion and malignant cytology are reliable with a specificity of 100%. In these cases, we recommend that the patients are considered for surgical or oncological treatment without further histological investigations.

Funding: not relevant.

Trial registration: not relevant.