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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) 0.200 was the strongest risk indicator (odds ratio as compared to that <0. Key words: population-based case-control study; inflammation; polymorphism; alcohol drinking; nitrosamine Cholangiocarcinoma is uncommon, and the aetiology has been elucidated only for a limited portion of cases.1 Northeast Thailand has an exceptionally high incidence of liver cancer of up to 87.5 (male) and 37.2 (female) per 100,000 (world population-adjusted incidence rate). Most of these cases have been attributed to cholangiocarcinoma.2 Infestation of the liver fluke, Opisthorchis viverrini (OV), has been causally related to cholangiocarcinoma in this region. 3 The prevalence of OV infection in Nakhon Phanom province was between 30 and 70% with substantial variation between villages; 4 the technique for estimation of prevalence was not explicitly mentioned but supposed OV egg counting in the faeces. However, it is unknown why only a limited proportion of the inhabitants (<10%) develop cholangiocarcinoma.In our study, we hypothesised that genetic background may be a contributing factor in the occurrence of the cholangiocarcinoma. Hence, we examined the association between polymorphisms of genes for glutathione-S-transferase enzymes, GSTM1 and GSTT1, and the risk for cholangiocarcinoma. Because both enzymes function in carcinogen detoxification systems, 5 it seems reasonable to speculate that null variants of these genes may be associated with increased risk of cancer. 6The association between OV infection and cancer risk has been a common assumption, but adequate analytic epidemiological studies are sparse. Parkin and colleagues 7 reported in their casecontrol study that past or present infection with OV, as indicated by serum antibodies against OV, is associated with a 5-fold increase in cancer risk. Although the anti-OV antigen titre was elevated and reached a plateau at an approximately 2 months after OV inoculation in hamsters, 8 the transition of the antibody level over the lifespan remains uncertain in both humans and animals. We thus examined the risk of foods possibly containing OV metacercariae as well as that of OV infection as indicated by serum antibody response.In animal experiments, OV infection causes cholangiocarcinoma with coadministration of nitrosamine 9 in a dose-dependent manner.10 Diet and cigarette smoking are major sources of nitrosamine exposure, 11 and several foods and foodstuffs consumed in the study ar...

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In Thailand, five cancer types—breast, cervical, colorectal, liver and lung cancer—contribute to over half of the cancer burden. The magnitude of these cancers must be quantified over time to assess previous health policies and highlight future trajectories for targeted prevention efforts. We provide a comprehensive assessment of these five cancers nationally and subnationally, with trend analysis, projections, and number of cases expected for the year 2025 using cancer registry data. We found that breast (average annual percent change (AAPC): 3.1%) and colorectal cancer (female AAPC: 3.3%, male AAPC: 4.1%) are increasing while cervical cancer (AAPC: −4.4%) is decreasing nationwide. However, liver and lung cancers exhibit disproportionately higher burdens in the northeast and north regions, respectively. Lung cancer increased significantly in northeastern and southern women, despite low smoking rates. Liver cancers are expected to increase in the northern males and females. Liver cancer increased in the south, despite the absence of the liver fluke, a known factor, in this region. Our findings are presented in the context of health policy, population dynamics and serve to provide evidence for future prevention strategies. Our subnational estimates provide a basis for understanding variations in region-specific risk factor profiles that contribute to incidence trends over time.