epidemiological results suggested an increase of cancer risk after
receiving computed tomography (CT) scans in childhood or adolescence.
Their interpretation is questioned due to the lack of information about
the reasons for examination. Our objective was to estimate the cancer
risk related to childhood CT scans, and examine how cancer-predisposing
factors (PFs) affect assessment of the radiation-related risk.
cohort included 67,274 children who had a first scan before the age of
10 years from 2000 to 2010 in 23 French departments. Cumulative X-rays
doses were estimated from radiology protocols. Cancer incidence was
retrieved through the national registry of childhood cancers; PF from
a mean follow-up of 4 years, 27 cases of tumours of the central nervous
system, 25 of leukaemia and 21 of lymphoma were diagnosed; 32% of them
among children with PF. Specific patterns of CT exposures were observed
according to PFs. Adjustment for PF reduced the excess risk estimates
related to cumulative doses from CT scans. No significant excess risk
was observed in relation to CT exposures.
study suggests that the indication for examinations, whether suspected
cancer or PF management, should be considered to avoid overestimation of
the cancer risks associated with CT scans.