Controversy exists about the association between occupational exposures to
vinyl chloride and
hepatocellular carcinoma and
cirrhosis. Two large multicentre mortality cohort studies, one American and another European, reported higher mortality for primary
cancer of liver and biliary tract. However, the American study was not able to rule out misclassification, because based on death certificates and under the heading primary
liver cancers, some
angiosarcomas, the typical
neoplasia associated with
vinyl chloride, may have been included. The American study does not report on
cirrhosis mortality. The European study also reports higher mortality of primary
liver cancer, but contrary to the American study in a further analysis based on 10 verified cases of
hepatocellular carcinoma, an exposure-response trend with duration of employment and with cumulative exposure to
vinyl chloride was detected. A smaller cohort belonging to this multicentre cohort confirmed these results. Meta-analyses based on the two large cohorts concluded for a small excess of primary
liver cancer, although misclassification could not be ruled out. Excess risk of
cirrhosis was reported in the European cohort, in a subcohort and in a cross-sectional study. However, a meta-analysis did not confirm this excess. Several critical appraisals of the literature reached antithetical conclusions about
hepatocellular carcinoma,
cirrhosis and occupational exposures to
vinyl chloride. For both
hepatocellular carcinoma and
cirrhosis, a study suggests an additive and multiplicative effect of
vinyl chloride exposure with viral
hepatitis and alcohol consumption respectively. Pathology reports seem to indicate a possible development of
hepatocellular carcinoma but not of
cirrhosis after high exposures to
vinyl chloride.