To investigate the role of cancer predisposing factors
(PFs) on the associations between paediatric computed tomography (CT)
scan exposures and subsequent risk of central nervous system (CNS)
tumours and leukaemia.
A cohort of children who underwent a CT
scan in 2000–2010 in 23 French radiology departments was linked with the
national childhood cancers registry and national vital status registry;
information on PFs was retrieved through hospital discharge databases.
children without PF, hazard ratios of 1.07 (95% CI 0.99–1.10) for CNS
tumours (15 cases) and 1.16 (95% CI 0.77–1.27) for leukaemia (12 cases)
were estimated for each 10 mGy increment in CT x-rays organ doses. These
estimates were similar to those obtained in the whole cohort. In
children with PFs, no positive dose-risk association was observed,
possibly related to earlier non-cancer mortality in this group.
results suggest a modifying effect of PFs on CT-related cancer risks,
but need to be confirmed by longer follow-up and other studies.