Alcoholic liver disease and risk of cholangiocarcinoma: a systematic review and meta-analysis

BACKGROUND: With the purpose of elevating the risk of cholangiocarcinoma (CCA), alcoholic liver disease (ALD) was shown. Nonetheless, the findings were controversial. Herein, a meta-analysis and a systematic review were conducted to study the relation as mentioned above. METHODS: This study searched PubMed, EMBASE, and SI Web of Science carefully for the related studies published prior to March 2018, followed by the random-effects model to calculate the values of pooled risk ratio with 95% CIs. In addition, the analyses of sensitivity and subgroup were carried out to further confirm the stability of the outcomes. RESULTS: Seven articles, consisting of 413,483 healthy controls and 8,962 CCA patients, were included in this meta-analysis. When compared with normal controls, patients with ALD had an enhanced 3.92-fold CCA risk, with studies being heterogeneous (95% CI =1.96–5.07; OR =3.92; I2 =70.2%). However, subgroup analysis showed that ALD had the enhanced risk of intrahepatic cholangiocarcinoma (ICC), instead of extrahepatic cholangiocarcinoma (ECC) (ICC: 95% CI =3.06–5.92, OR =4.49; ECC: 95% CI =0.90–3.35, OR =2.12). Additionally, when the analysis was stratified by the geographic area, positive association was observed only in western countries rather than eastern countries (western nations: 95% CI =3.34–6.96, OR =5.15; eastern nations: 95% CI =0.38–3.91, OR =2.14). And no essential bias was published. CONCLUSION: ALD was greatly associated with the enhanced risk of CCA by 3.92-fold, especially in the ICC.