Factors that modify risks of radiation-induced cancer.
The collective influence of biologic, physical, and other factors that modify risks of radiation-induced cancer introduces uncertainties and assumptions that limit precision of estimates of human cancer risk that can be calculated for populations exposed to low-dose radiation. The important biologic characteristics include the tissue sites and cell types, baseline cancer incidence, latent periods, time-to-tumor recognition, and individual host (e.g., age and sex) and competing etiologic influences. Physical factors include radiation dose, dose rate, and radiation quality. Statistical factors include time-response projection models, risk coefficients, and dose-response relationships. Sources that modify risk also include other carcinogens and biologic factors (e.g., hormonal conditions, immune status, hereditary factors). Discussion includes examples of known influences that modify radiation-associated cancer risks and how they have been dealt with in the risk-estimation process, including extrapolation to low doses, use of relative risk models, and other uncertainties.
Fabrikant
J I
JI
Donner Laboratory, University of California, Berkeley 94720.
D003043:Cocarcinogenesis; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008954:Models, Biological; D009381:Neoplasms, Radiation-Induced / Q000209:etiology*; D011829:Radiation Dosage; D012307:Risk Factors