Long-term outcome and prognostic factors of intrahepatic cholangiocarcinoma involving the hepatic hilus versus hilar cholangiocarcinoma after curative-intent resection: Should they be recognized as perihilar cholangiocarcinoma or differentiated?

Background: Perihilar cholangiocarcinoma is defined as tumors arising predominantly at or near the biliary confluence, potentially consisting of two types: hilar cholangiocarcinoma (HC) and intrahepatic cholangiocarcinoma involving the hepatic hilum (hICC). However, whether hICC and HC should be strictly distinguished or combined remains highly controversial. We aimed to compare the clinicopathological characteristics, prognostic factors and long-term outcome of hICC versus HC after curative-intent resection. Methods: Between January 1998 and June 2015, a total of 325 patients with hICC (n = 146) and HC (n = 179) who underwent curative-intent resection were enrolled. The medical records of these patients were retrospectively reviewed. Results: Portal vein invasion, larger tumors, and later T stage were significantly more common in hICC group. A total of 110 (75.3%) hICC patients and 119 (66.5%) HC patients experienced tumor recurrences, respectively. The median recurrence-free survival (RFS) and overall survival (OS) of hICC patients were significantly worse than those of HC patients (median RFS, 14.3 versus 22.7 months, P= 0.014; median OS, 21.7 versus 30.6 months, P = 0.032). Multivariate analysis revealed tumor size, satellite nodules, surgical margin, and histological grade as independent factors for OS in hICC patients. On the other hand, the presence of liver parenchyma invasion, portal invasion, lymphovascular invasion, later N stage, and positive surgical margin were associated with shorter OS in HC patients. Conclusions: hICC showed distinct clinicopathological features, more aggressive biological behaviors, different prognostic factors, and worse prognosis in comparison with HC. Therefore, making a strict distinction between hICC and HC is necessary. (C) 2019 Published by Elsevier Ltd.