ICRP Publication 79: Genetic Susceptibility to Cancer

ICRP Publication 79 provides an extensive discussion of hereditary variations in the susceptibility to cancer, and includes a commentary on the possible implications of such susceptibility variations for radiological protection. Current ICRP recommendations are based essentially on the estimation of excess cancer risk after exposure of whole populations. Because of differences in genetic make-up between individuals, there is a strong expectation that the excess cancer risk per unit dose of radiation exposure will be non-uniform. The report seeks to review relevant data and make interim judgments on tumorigenic radiosensitivity in the genetic disorders of this type, and also on the likely contribution that genetic factors may make to radiation-induced cancer. Since directly informative epidemiological data on radiation effects under differing cancer predispositions are essentially lacking, emphasis is placed on experimental studies and clinical observations, on computational genetic models of cancer risk, and on possible research strategies for the future. This provides a framework facilitating future judgments in this rapidly advancing area of human genetics. At this stage, the utility of genetic testing for cancer predisposition is limited by technical factors and concerns on predictive power. The preliminary conclusion is that in the future, genetic testing may find selected use prior to certain medical exposures to radiation, but apart from that, genetic testing for cancer disorders seems unlikely on current knowledge to attain a major role in radiation protection practice.