A work-relatedness assessment in epidemiological case investigation of occupational cancers: I. Principles.

It is important to identify the causal relationship between occupational exposure and the disease in the area of compensation because most cancers have long latent period. This review presents the principles that should be considered when evaluating the work-relatedness. We reviewed reports on occupational cancers published by the International Agency for Research on Cancer, American Conference of Governmental Industrial Hygienists, National Toxicology Program, Environmental Protection Agency, European Union, which are the world's most prestigious organizations. In addition, we reviewed relevant papers and books published in Korea. The process is conducted in the order of cancer diagnosis, exposure assessment for carcinogens, and work-relatedness assessment. The probability of causation is determined stochastically rather than deterministically. There is no absolute standard for accreditation criteria and results may vary according to expert opinions and in each country or organization. Revealing the causal relationship of occupational cancers is a difficult process owing to inconsistency in relevant epidemiological studies, lack of well-established biological mechanisms, loss of objective occupational historical data, and other complexity of individual cases. Causation is unclear in many cases. Nevertheless, the data should be reviewed in detail for each case suspected of work-related cancers, and an assessment should be made through valid and plausible logic and literature evidences.