Cholangiocarcinoma and Clonorchis sinensis infection: A case–control study in Korea

Background/Aims The authors conducted a hospital-based case–control study to evaluate the role of Clonorchis sinensis infection as a risk factor for the development of cholangiocarcinoma (CC), including extrahepatic CC, in Korea. Methods Cases of 185 patients with CC (intrahepatic, 51; hilar, 53; and distal extrahepatic, 81) and matched controls underwent stool microscopy, pathological examinations, serologic test for C. sinensis using ELISA, skin test for C. sinensis, radiologic examinations, and interview concerning history of eating raw freshwater fish. Results Radiologic evidence of C. sinensis, history of eating raw freshwater fish, and positive serologic result for C. sinensis were found to be related to an increased risk of CC, with the odds ratios (OR)=8.615 (95% confidence interval [CI]=5.045–16.062), OR=2.385 (95% CI=1.527–3.832), and OR=2.272 (95% CI=1.147–4.811), respectively. The risk factors for distal extrahepatic CC were radiologic evidence of C. sinensis (OR=6.571; 95% CI=3.170–15.943) and history of eating raw freshwater fish (OR=2.6; 95% CI=1.294–5.66). Conclusions Radiologic evidence of C. sinensis, history of eating raw freshwater fish and positive serologic result for C. sinensis were significantly associated with CC, including extrahepatic CC.