A Comparison of Cytology and Fluorescence In Situ Hybridization for the Detection of Malignant Bile Duct Brushing Specimens
J Zhai. Cedars-Sinai Medical Center, Los Angeles, CA
Background: The routine bile duct brushing cytology is an important diagnostic tool in the evaluation of patients with bile duct stricture. The routine cytology has high specificity but rather poor sensitivity for the detection of malignancy. The leading causes of malignant biliary tract stricture are cholangiocarcinoma and pancreatic adenocarcinoma, which are characterized by high frequency of numerical and structural chromosomal abnormalities. Fluorescence in situ hybridization (FISH) is a valuable tool to detect chromosomal abnormalities. The UroVysion FISH probes (Abbott Laboratories) are originally developed for the detection of urothelial cancer, and contain probes to the cnetromeres of chromosome 3, 7 and 17, and chromosomal band 9p21. The purpose of this prospective study is to evaluate the performance of UroVysion FISH assay over routine cytology for the detection of malignant bile duct brushing specimens.
Design: Thirty five consecutive patients who underwent ERCP and bile duct brushing for bile duct stricture in a period of 6 months were included in the study. The smears for routine cytology were prepared first using Thin Prep technology. The smears for FISH were made from the residue using cytospin preparation. The FISH analysis utilized the commercially available UroVysion probes. The FISH was reported positive if > 4 cells showed gains for >2 chromosomes. The indeterminate cytology results were considered as negative for statistical analysis.
Results: Twenty two of 35 patients were diagnosed of malignancy (22 adenocaricnoma and 1 multiple myeloma) based on biopsy, fine needle aspiration or clinical progression of disease. The sensitivity of routine cytology and FISH for the detection of malignancy was 14% (3/22) and 55% (12/22) respectively (p=0.003). The specificity of routine cytology and FISH was 100% (13/13) and 62% (8/13) respectively (p=0.025).
Conclusions: Our study shows that FISH is significantly more sensitive than routine cytology for the detection of malignancy in bile duct brushing specimens. However, the specificity of FISH is extremely poor in our study, compared to routine cytology with excellent specificity. A larger study is necessary to further evaluate the performance of FISH in the detection of malignancy in bile duct brushing specimens.
Wednesday, March 11, 2009 1:00 PM
Poster Session VI # 46, Wednesday Afternoon