P-186 Vimentin-positive circulating tumor cells as diagnostic and prognostic biomarkers in biliary tract cancer patients

Abstract

Biliary tract cancer (BTC) has poor prognosis and its mortality is higher than other gastrointestinal malignancies. Early diagnosis of BTC is important to decrease the mortality. Vimentin-positive circulating tumor cells (V-CTCs) are a good candidate for diagnostic biomarkers. However, there are limited studies regarding the role of V-CTCs as diagnostic and prognostic biomarkers in BTC patients. The aim of this study was to evaluate the diagnostic efficacy of V-CTCs between BTC and benign biliary disease (BBD) and determine the prognostic value of V-CTCs in BTC patients. We recruited 69 participants who has BTCs and BBDs from a single tertiary referral center between June 2018 and February 2021. We analyzed CTCs and V-CTCs using peripheral blood by CD-PRIMETM system, which is a commercialized version of the FAST disc (Clinomics, Ulsan, Korea). CTCs were detected in 62 of 69 (90%) patients. CTC count > 40/ml blood (20% Vs 55.8%, p=0.039), V-CTC > 15/ml blood (10% Vs 57.7%, p=0.005) and V-CTC/CTC ratio > 40% (10% Vs 48.1%, p=0.025) were significantly different between BTCs and BBDs. And two or more of these parameters (10% Vs 61.5%, p=0.002) increased the accuracy of distinguishing between BTCs and BBDs. Moreover, the combination of circulating tumor markers with elevated CA19-9 and biopsy, increased the accuracy (10% Vs 90.4%, p=0.000). Combination of circulating tumor markers with elevated CA19-9 (10%, Vs 84.8%, p=0.000) and biopsy (10% Vs 87.9%, p=0.000) was also distinguished between BBD and resectable BTC. In terms of prognosis, V-CTC > 50/ml blood was a significantly influencing factor of survival (140 days Vs 253 days, p=0.008). The combination of circulating tumor markers with elevated CA19-9 and/or biopsy may discriminate early stage of BTC from BBD, and V-CTC could determine future prognosis in patients with BTC.