Improve the diagnosis of biliary cancers by fluorescent in situ hybridization in brush samples

Aim: We investigated the diagnostic value of Fluorescent in situ hybridization (FISH) (UroVysion kit) for the bile duct carcinoma in brush samples, comparing to the clinical methods such as ERC and IDUS.

Methods: The anueploidy was prevalent in tumors. We detected anueploidy in brush samples of biliary cytology by FISH. UroVysion kit was chosen for FISH in this study, as it has been widely used in cytological diagnosis for tumors and approved by FDA. The diagnostic value of FISH was assessed and compared with that of routine cytology (RC) and the biliary imaging methods, such as ERC and IDUS. The gold standard was established by the pathological diagnosis or clinical outcome after 6-months follow-up.

Results: Totally, we got brush samples from 27 patients in which 22 were diagnosed as malignancy. The cytological diagnostic value of the bile duct carcinoma was improved by FISH (UroVysion) detecting anueploidy in brush samples. The sensitivity, specificity, positive predictive value and negative predictive value are 50%, 100%, 100%, and 31.3% respectively by FISH, and are 22.7%, 100%, 100%, and 22.7% respectively by RC. Combined RC and FISH, the diagnostic sensitivity is 63.5% (compare to RC, p=0.004). The malignant diagnoses were established by ERC in 7 patients. In another 15 patients who only presented strictures on ERC, 8 samples were positive by FISH assay. There're 23 patients who received IDUS. The sensitivity and specificity were 83.3% (15/18) and 75.0% (3/4) respectively. Combined IDUS and FISH, the diagnostic sensitivity increased to 86.4% (19/22).