Lung cancer screening by low-dose computed tomography: A modelling study to evaluate radiation-induced cancer risks, and the influence of smoking behavior
Menée en France à partir de données de la littérature scientifique et de modélisations, cette étude estime, en fonction du comportement tabagique, le ratio bénéfice/risque (nombre de décès évités / nombre de cancers radio-induits) de dépistages répétés du cancer du poumon par tomographie numérique à faible dose de rayonnement
Introduction : Lung cancer screening using low-dose computed tomography (LDCT) is being experimented in France. Based on the terms of a French pilot program, we estimated the risk of radiation-induced cancer for six cancer sites exposed to ionizing radiation during LDCT.
Materials and methods : Three groups were considered according to smoking behavior. Baseline cancer risks in smokers were computed based on available data and literature. Radiation-induced risks of cancer following repeated LDCT from age 50 until loss of eligibility to screening, were estimated based on two reference radiation-risks models, assuming a complete adherence to the program, and a volume computed tomography dose index (CTDIvol) of 0·8 mGy. A benefit-risk ratio was estimated considering 5-year cancer mortality in France, and screening lung cancer specific mortality decrease, as reported in literature.
Results : We estimated a lifetime attributable risk of 16 radiation-induced cancers per 100,000 screened women (7 in men, respectively), including 9 (3) lung cancers, and 2 (0) breast cancers, leading to 10 (5) deaths. Compared to 232 (162) expected lung cancer deaths prevented, this leads to an estimated ratio of 23 (32). Because smoking cessation improve survival rates and decrease lung cancer incidence rates, ceasing groups face lower benefit-risk ratios: it is close to 1 in individuals weaned 15 years before screening inclusion.
Conclusion : Our results show that the number of radiation-induced cancers following repeated LDCT remains low compared to prevented deaths, as long as weaning is recent. It underlines the importance of efforts to reduce the dose to ensure that all enrolled individuals face a favorable ratio.
Cancer Epidemiology , résumé, 2026