[Causality in occupational oncology: the toxicologist opinion].

General and individual causality in occupational oncology should be regarded as diverse and largely autonomous concepts. General causality is based upon a statement such as "the chemical is a carcinogen" and must be considered for preventive action. Individual causality implies that the statement has to be applied to a patient exposed to that chemical. Whereas cancer results from complex interactions between genes and, in broad sense, the environment, the individual causality is an empirical judgement (educated guess) based upon all information about the substance itself and the individual patient.