These evaluations represent only one part of the body of information on which regulatory measures may be based. The evaluations of IARC working groups are scientific, qualitative judgements about the evidence for or against carcinogenicity provided by the available data. The Monographs may assist national and international authorities in making risk assessments and in formulating decisions concerning any necessary preventive measures. Information on mechanisms may, however, be used in making the overall evaluation ( IARC, 1991a Vainio et al., 1992 see also pp. The aim of the Monographs has been, from their inception, to evaluate evdence of carcinogenicity at any stage in the carcinogenesis process, independently of the underlying mechanisms. Some epidemiological and experimental studies indicate that different agents may act at different stages in the carcinogenic process, and several different mechanisms may be involved. The terms ‘neoplasm’ and ‘tumour’ are used interchangeably. 19) contribute to the judgement that the exposure is carcinogenic. The term ‘carcinogen’ is used in these monographs to denote an exposure that is capable of increasing the incidence of malignant neoplasms the induction of benign neoplasms may in some circumstances (see p. Quantitative extrapolation from experimental data to the human situation is not undertaken. Detailed, quantitative evaluations of epidemiological data may be made in the Monographs, but without extrapolation beyond the range of the data available.
The second step is quantitative risk estimation. The Monographs represent the first step in carcinogenic risk assessment, which involves examination of all relevant information in order to assess the strength of the available evidence that certain exposures could alter the incidence of cancer in humans. The Monographs may also indicate where additional research efforts are needed. The objective of the programme is to prepare, with the help of international working groups of experts, and to publish in the form of monographs, critical reviews and evaluations of evidence on the carcinogenicity of a wide range of human exposures. The criteria established in 1971 to evaluate carcinogenic risk to humans were adopted by the working groups whose deliberations resulted in the first 16 volumes of the IARC Monographs series.
With Supplement 6 ( IARC, 1987a), the title of the series was modified from IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans to IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, in order to reflect the widened scope of the programme. The Monographs programme has since been expanded to include consideration of exposures to complex mixtures of chemicals (which occur, for example, in some occupations and as a result of human habits) and of exposures to other agents, such as radiation and viruses. In 1969, the International Agency for Research on Cancer (IARC) initiated a programme to evaluate the carcinogenic risk of chemicals to humans and to produce monographs on individual chemicals.