LAUSR

205 Background: Intrahepatic cholangiocarcinoma (IHCC) is known as one of most malignant cancers. Recently, the vascularity in the hepatic arterial phase (HAP) of dynamic CT has been reported as a possible prognostic marker in IHCC. The aim of this study is to elucidate the role of central hypovascularity in the HAP on mass-forming IHCC. Methods: Forty patients who underwent initially hepatic resection for mass-forming IHCC were enrolled. The HAP was scanned 40 seconds after the injection of contrast agent. Vascular pattern was classified into three groups; hypervascularity (Hyper) group (n = 8), rim-enhancement (Rim) group (n = 7) and hypovascularity (Hypo) group (n = 25) by a radiologist in reference to Fujita, et al (Eur Radiol 2017). Hypoxia-inducible factor-1 (HIF-1) expression in the surgical specimen was evaluated by immunohistochemistry. The clinicopathological findings were compared among the groups. Results: The advanced stage tended to be more frequent in Hypo group, however, no difference of tumor location (hilar or peripheral) was observed. Overall survival (OS) in Hypo group was worse than that in Hyper group. The OS in Rim+Hypo group, that means central hypovascularity in the tumor, was worse than that in Hyper group. Furthermore, Rim+Hypo group was an independent prognostic factor in OS (HR: 5.44). Regarding the HIF-1 expression, high HIF-1 expression in the central part of the tumor correlated with central hypovascularity in the HAP (25% in Hyper-group and 72% in Rim+Hypo group, respectively). Conclusions: The central hypovascularity (Rim+Hypo group) was an independent prognostic factor, furthermore, high malignant potential of the tumor with central hypovascularity might be related to HIF-1 upregulation.