Department of Hepatology, St Mary's Hospital, Imperial College London, London, United Kingdom.
Center of Applied Biomedical Research, S. Orsola-Malpighi University Hospital, Bologna, Italy.
Liver Int. 2019 May;39 Suppl 1:19-31. doi: 10.1111/liv.14095. Epub 2019 Mar 24.
Cholangiocarcinoma (CCA) is a heterogeneous disease arising from a complex interaction between host-specific genetic background and multiple risk factors. Globally, CCA incidence rates exhibit geographical variation, with much higher incidence in parts of the Eastern world compared to the West. These differences are likely to reflect differences in geographical risk factors as well as genetic determinants. Of note, over the past few decades, the incidence rates of CCA appear to change and subtypes of CCA appear to show distinct epidemiological trends. These trends need to be interpreted with caution given the issues of diagnosis, recording and coding of subtypes of CCA. Epidemiological evidences suggest that in general population some risk factors are less frequent but associated with a higher CCA risk, while others are more common but associated with a lower risk. Moreover, while some risk factors are shared by intrahepatic and both extrahepatic forms, others seem more specific for one of the two forms. Currently some pathological conditions have been clearly associated with CCA development, and other conditions are emerging; however, while their impact in increasing CCA risk as single etiological factors has been provided in many studies, less is known when two or more risk factors co-occur in the same patient. Moreover, despite the advancements in the knowledge of CCA aetiology, in Western countries about 50% of cases are still diagnosed without any identifiable risk factor. It is therefore conceivable that other still undefined etiologic factors are responsible for the recent increase of CCA (especially iCCA) incidence worldwide.
胆管癌（CCA）是一种异质性疾病，由宿主特异性遗传背景与多种风险因素之间的复杂相互作用引起。在全球范围内，CCA 的发病率存在地域差异，与西方相比，东方世界的发病率更高。这些差异可能反映了地域风险因素以及遗传决定因素的差异。值得注意的是，在过去几十年中，CCA 的发病率似乎发生了变化，并且 CCA 的亚型似乎表现出明显的流行病学趋势。鉴于 CCA 亚型的诊断、记录和编码问题，需要谨慎解释这些趋势。流行病学证据表明，在一般人群中，一些风险因素不太常见但与更高的 CCA 风险相关，而另一些则更为常见但与更低的风险相关。此外，虽然一些风险因素与肝内和肝外两种形式都有关，但其他因素似乎更特定于其中一种形式。目前，一些病理状况已明确与 CCA 的发生有关，其他状况也在不断涌现；然而，虽然在许多研究中已经提供了这些风险因素作为单一病因因素对增加 CCA 风险的影响，但当两个或更多风险因素同时存在于同一患者中时，其影响知之甚少。此外，尽管对 CCA 病因学的认识有所提高，但在西方国家，仍有约 50%的病例没有任何可识别的风险因素。因此，可以想象，其他尚未明确的病因因素可能是导致全球范围内 CCA（尤其是 iCCA）发病率最近增加的原因。
