Cancer risk of low dose ionizing radiation: new insights from modern biology provoke more questions and challenges

Started in January 2004, the project carried out research to contribute to the improvement of the management of health risks attributable to low dose exposures, i.e. 100 mSv or less.

New evidence concerning the processes that drive radiation carcinogenesis has been obtained. Some evidence was given that high and low dose responses can differ, and that a range of dose response relationships exist for cancer relevant phenomena. Animal models provide evidence of a link between direct radiation-induced genome change and cancer. Moreover non-targeted phenomena can also contribute.

Evidence was also gathered on the role of genetic factors in modifying risk in individuals and population sub-groups. These results do not point to a need to reconsider the use of LNT approaches to cancer risk projection but does highlight the complexity of the biological response to radiation at different dose levels particularly when considered at the level of the whole organism.

The consortium of 36 European partner labs focussed their efforts on radiation cancer risk and cover a wide range of scientific expertise from basic radiobiology through to cancer risk modelling. The project was supported by the European Commission Euratom programme with a contribution of 10 million Euro. It has overall harvested the resources of 31 institutions, 90 researchers, 28 post doctoral workers and 53 PhD students and an estimated overall project budget of 30 million Euro to address the problem of quantification of radiation cancer risk at low doses.

In the course of the project 163 scientific papers have been published and 51 PhD students trained. Wider outreach within the radiation protection community has been achieved through project members involvement in key radiation protection and radiobiology meetings such as UNSCEAR, IRPA, National health councils, Radiation Research, ESRB and the US Low Dose program meeting.

The results of the project and their relevance to radiation protection have been highlighted in a conference open to the public on October 8. Attended by about 100 people, it took place in the CEA research center in Fontenay-aux-Roses, France, the homeland of RISC-RAD and the workplace of the project coordinator, Laure Sabatier, who runs the laboratory of radiobiology and oncology in the Institute of Cellular and Molecular Radiobiology. The videos of the conference are accessible online from the following URL : www.riscrad.org

Two documents summarizing RISC-RAD research will be produced : “Improving the evidence base for radiation protection” and the scientific summary. Both will be available freely from November 2008 at www.riscrad.org.