Background: Infection with liver flukes has been reported to be associated with bile duct malignancy.
Methods: The review is based on a literature search (Medline) and, in some cases, direct contact with authors or principal investigators.
Results: A large body of evidence indicates that Opisthorchis viverrini is a definite cause of human cholangiocarcinoma, whereas Clonorchis sinensis is a probable cause. The evidence regarding Opisthorchis felineus is insufficient to assess its role in carcinogenesis. Possible mechanisms of carcinogenesis include chronic irritation, nitric oxide formation, intrinsic nitrosation and activation of drug-metabolizing enzymes. Early detection of bile duct malignancy is difficult and not clinically available at present, although cholangiocarcinoma-associated soluble antigen has been reported in an experimental study to be a useful early marker of cancer development. Long-term survival after surgical treatment of liver fluke-associated cancer is similar to that reported in patients without liver fluke infestation.
Conclusion: Liver fluke-associated cholangiocarcinoma is still a health problem in developing countries. Mechanisms of carcinogenesis should be explored further in order to reduce the impact of this disease.