The radiation epidemiology of cancer - where do we stand now?

Much has been learnt from epidemiological studies about the risk of cancer consequent to exposure to ionising radiation. These studies have investigated the influence of radiation exposure upon cancer risk in the Japanese atomic bomb survivors, patients exposed for medical reasons, workers exposed occupationally, and members of the public receiving doses from various environmental sources of radiation. Findings from radiation epidemiology continue to be published, casting light on many aspects of radiation-related cancer risks. Continued follow-up of the bomb survivors has revealed excess cancer risks among those exposed at a young age many years later, and there is emerging evidence of upward curvature in the dose-response for all solid cancers combined. The rise of computed tomography (CT) examinations in medical diagnostic investigations presents an opportunity to study low dose risks, although caution is required in the interpretation of medical studies. Analyses of pooled nuclear worker data provide increasingly powerful investigations of the risks of protracted low-level exposures, particularly because lengthening follow-up has led to an expanding database for early workers who tended to accumulate higher doses than later workers. This paper reviews recent findings of epidemiological studies of radiation exposure and cancer risk that were available at the end of 2022.