Risk of hepatocellular carcinoma in workers exposed to chemicals

Abstract

Context: Studies on experimental animals have shown liver is a common target of chemical carcinogens; this might suggest that occupational exposure to chemicals is another risk factor for HCC. However, the relationship between occupation and liver cancer has not been extensively studied, with the exception of the known association between vinyl chloride and angiosarcoma of the liver.

Evidence acquisition: A MEDLINE and conventional search of the past 50 years of the medical literature was performed to identify relevant articles on incidence and mechanisms of HCC due to occupational exposure to chemicals. Several important edited books and monographs were also identified and reviewed.

Results: While laboratory data clearly indicate that the liver is an important target of chemical carcinogenesis, epidemiological studies provide very limited evidence on occupational risk factors for HCC. Nevertheless, we found some case reports and epidemiological data showing a moderately increased risk of HCC development in people exposed to vinyl chloride, organic solvents, pesticides, polychlorinated biphenyls, and arsenic.

Conclusions: Occupational exposure to chemicals may be another risk factor for HCC development, but the interpretation of currently available findings is limited by the small number of studies, questionable accuracy of the diagnosis of liver cancer, and potential confounding or modifying factors such as chronic hepatitis virus infection and alcohol consumption. Further relevant investigations are required for clarifying the actual contribution of occupational exposure to chemicals in HCC development.

Keywords: Arsenic; Carcinoma, Hepatocellular; Occupational Exposure; Pesticides; Polychlorinated Biphenyls; Solvents; Vinyl Chloride.

Figure 1. Chemical Structure of Vinyl Chloride Monomer

Figure 2. Chemical Structure of 1,1,1-Trichloro-2,2-bis(p-chlorophenyl) ethane (DDT)

Figure 3. Chemical Structure of Polychlorinated Biphenyls