1. Risk factors for intrahepatic and extrahepatic cholangiocarcinoma: A systematic review and meta-analysis
- Author
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Simon D. Taylor-Robinson, Oliver Clements, Shahid A. Khan, Joseph Eliahoo, and Jin Un Kim
- Subjects
0301 basic medicine ,Cirrhosis ,LIVER ,MORTALITY-RATES ,HEPATITIS-B-VIRUS ,Hepacivirus ,Gastroenterology ,Cholangiocarcinoma ,0302 clinical medicine ,Bile Ducts, Extrahepatic ,Risk Factors ,POPULATION ,Liver Cirrhosis, Biliary ,Incidence (epidemiology) ,Incidence ,Hepatitis B ,Hepatitis C ,Meta-analysis ,BILE-DUCT CANCERS ,030211 gastroenterology & hepatology ,Life Sciences & Biomedicine ,medicine.medical_specialty ,Hepatitis B virus ,Alcohol Drinking ,UNITED-STATES ,1117 Public Health and Health Services ,03 medical and health sciences ,ASPIRIN USE ,Internal medicine ,medicine ,Humans ,Choledochal cysts ,Hepatitis ,Science & Technology ,Hepatology ,Gastroenterology & Hepatology ,business.industry ,DIABETES-MELLITUS ,1103 Clinical Sciences ,Publication bias ,Odds ratio ,medicine.disease ,BILIARY-TRACT CANCER ,030104 developmental biology ,Bile Ducts, Intrahepatic ,Bile Duct Neoplasms ,Case-Control Studies ,business ,INFLAMMATORY-BOWEL-DISEASE - Abstract
Background & Aims Cholangiocarcinoma (CCA) carries a poor prognosis, is increasing in incidence and its causes are poorly understood. Although some risk factors are known, they vary globally and collectively account for a minority of cases. The aim of this study was to perform a comprehensive meta-analysis of risk factors for intrahepatic (iCCA) and extrahepatic cholangiocarcinoma (eCCA), from Eastern and Western world studies. Methods A literature search of case-control studies was performed to identify potential risk factors for iCCA and eCCA. Pooled odds ratios (ORs) with 95% CIs and heterogeneity were calculated. Funnel plots were used to assess publication bias, and meta-regression was used to select risk factors for comparison between Eastern and Western studies. Results A total of 13 risk factors were selected from 25 case-control studies in 7 geographically diverse countries. The strongest risk factors for both iCCA and eCCA were biliary cysts and stones, cirrhosis, hepatitis B and hepatitis C. Choledochal cysts conferred the greatest risk of both iCCA and eCCA with pooled ORs of 26.71 (95% CI 15.80–45.16) and 34.94 (24.36–50.12), respectively. No significant associations were found between hypertension and obesity for either iCCA or eCCA. Comparing Eastern and Western populations, there was a difference for the association of hepatitis B with iCCA (coefficient = −0.15195; 95% CI −0.278 to −0.025; p = 0.022). Conclusion This is the most comprehensive meta-analysis of CCA risk factors to date. Some risk factors, such as diabetes, although less strong, are increasing globally and may be contributing to rising rates of this cancer. Lay summary Cholangiocarcinoma (CCA) is a cancer arising in the bile ducts inside (intrahepatic CCA) and connected to the liver (extrahepatic CCA). It is a very aggressive cancer: 95% of patients die within 5 years. CCA rates are increasing globally, but the causes of CCA are poorly understood. The few risk factors that are known account for only a minority of cases. In this study, we found that the strongest risk factors for both intrahepatic and extrahepatic CCA are cysts and stones in the bile ducts, cirrhosis, and hepatitis B and C viruses. Some risk factors for CCA, such as diabetes, although less strong, are increasing globally and may be contributing to rising rates of CCA.
- Published
- 2019