Established risk factors for cholangiocarcinoma (CC)
| Risk factor | References and details |
| Age | 65% of patients aged >65 years17 19 |
| Chronic intraductal gallstones | Particularly in Asia where up to 10% of patients with hepatolithiasis (oriental cholangiohepatitis) develop intrahepatic CC17 19 15 17 19 |
| Bile duct adenoma and biliary papillomatosis | |
| Choledochal (bile duct) cysts and Caroli's disease (intrahepatic biliary cysts) | Lifetime risk of CC of 6–30%; risk of CC increases with age, and the average age of CC detection is in the fourth decade, younger than sporadic CC15 19 |
| Thorotrast | Radiological agent is no longer licensed for use, although risk of CC induced by Thorotrast lasts several decades15 16 |
| Liver flukes (Opisthorcis viverrini and Clonorchis sinensis) | South-east Asia such as north-east Thailand where CC is relatively common13 19 |
| Chronic typhoid carriage | South-east Asia; sixfold increased risk of all hepatobiliary malignancy13 19 |