Speaker
Dr
Simona Pazzaglia
(Laboratory of Radiation Biology and Biomedicine, ENEA , Rome, Italy)
Description
Exposure to ionizing radiation produces deleterious consequences in humans, including cancer. Although quantitative radiation effects are well established at high doses, considerable uncertainties persist about radiation-induced cancer in the low-dose region. Given our current state of knowledge, the model applied by regulatory bodies is based on the evidence that DNA damage, causing mutation and cancer, increases linearly with dose, and therefore relies on a linear extrapolation of cancer risk from high to intermediate and low doses.
A more complete understanding of the mechanisms of action of radiation at low doses might help define the shape of the dose-response curve, decreasing the uncertainties associated with cancer risk estimates in the low-dose region.
The use of tumor data from animal studies is necessary as a complement of epidemiological studies of human populations to develop estimates of relative risk at low doses. In addition, animal experiments provide valuable insights into the mechanisms of radiation interaction with living cells and organisms, allowing clarification of the pathways of tumorigenesis and of the factors modifying radiation risks. We have employed a mouse model of radiogenic CNS cancer to assess the tumorigenic potential of exposure to low-intermediate doses of radiation. Our in vivo findings have identified a linear dose–response in the low-dose region for several biological endpoints, such as tumor-free survival, apoptosis, and tumor induction in the range of 100-500mGy. This presentation will provide examples of recent tumor data from mouse studies demonstrating important implications of radiation dose on the final tumor outcome. These data highlight the complexity underlying low-dose radiation carcinogenesis, and might contribute to more complete understanding of low-dose cancer risk.
Primary author
Dr
Simona Pazzaglia
(Laboratory of Radiation Biology and Biomedicine, ENEA , Rome, Italy)
