Hepatitis viruses and risk of cholangiocarcinoma in northeast Thailand.

Liver cancer is the most common cancer in males in Thailand and the third in females. A high incidence of cholangiocarcinoma (CCA) is estimated in the northeast of Thailand. Chronic infection with Opisthorchis viverrini (OV) is the major risk factor for development of CCA. It has been demonstrated that HCV infection is a risk factor for CCA in non - endemic area of OV infection. We examined the association of HBV and HCV and risk of CCA in the northeast Thailand. All cases of CCA were recruited between 1999 and 2001 from Nakhon Phanom provincial hospital and all community hospitals in the province. One control per case was selected, matched by sex, age (∓5 years) and residence. 106 case-control pairs were obtained. Anti-OV, HBsAg, and Anti HCV were determined by ELISA. Among 103 age-sex-place of residence matched case-control pairs, there were 7, 0, 0, 96 pairs for anti-HCV (+) case vs. (-) control, (+) case vs. (+) control, (-) case vs. (+) control and (-) case vs. (-) control combinations (OR=7/0). Among 106 matched pairs, there were 9, 2, 4, 91 pairs for the similar four combinations of HBsAg (OR=2.25 (95%CI: 0.63-10.0). If the subject had anti-HCV and/or HBsAg, the OR for CCA was 4.00 (95%CI: 1.29-16.4). Even after adjustment for anti-OV, risk for HBsAg and/or anti-HCV positive was still marginally increased with an OR of 4.69 although not reaching statistical significance (95%CI: 0.98-22.5). Hepatitis B and C virus infection may also play role in the development of CCA in northeast Thailand.

Genetic and environmental determinants of risk for cholangiocarcinoma via Opisthorchis viverrini in a densely infested area in Nakhon Phanom, northeast Thailand.

Infection with Opisthorchis viverrini (OV) is associated with cholangiocarcinoma. OV is common in northeast Thailand, but less than 10% of the inhabitants develop cholangiocarcinoma. Animal experiments suggest that OV infection alone does not cause cholangiocarcinoma, and thus other environmental and genetic factors may play a role in causation. We conducted a population-based case-control study in which sex, age and place of residence were matched individually. Polymorphisms of GSTM1 and GSTT1 alone were not associated with risk for cholangiocarcinoma, while an elevated level of antibodies against OV (ELISA) > or = 0.200 was the strongest risk indicator (odds ratio as compared to that <0.200 = 27.09 [95% confidence interval (CI): 6.30-116.57]. Compared to subjects who had a normal antibody range and the wild-type GSTM1 gene, those who had elevated antibodies had higher odds ratios of 10.34 (95% CI: 1.31-81.63) [corrected] for wild-type GSTM1 and 18.00 (95% CI: 3.33-97.40) [corrected] for the null variant thereof, respectively. Past and current regular drinkers of alcohol had higher risk [odds ratio = 5.39 (95% CI: 1.11-26.06) and 4.82 (95% CI: 1.29-18.06), respectively]. Eating fermented products was an independent risk factor. Smokers or consumers of fermented fish had substantially increased risk if they were past or current drinkers. Infection with OV correlates strongly with cholangiocarcinoma, susceptibility to which may be possibly associated with GSTM1 polymorphism. Alcohol may affect metabolic pathways of endogenous and exogenous nitrosamines.