Paediatric CT scans are associated with up to four-times increased risk of later diagnosis of brain tumour, a Dutch study suggests.
The retrospective study found five-year post-CT cancer incidence was 1.5 times higher among children who had undergone a CT compared to the general population (standardised incidence ratio (SIR) 1.47; 95% CI 1.34-1.61).
For all brain tumours combined, and for malignant and nonmalignant tumours separately, relative risk increased to between two and four for the highest dose category (≥120mGy). Excess relative risks (ERRs) per 100mGy organ dose were 0.86 (95% CI 0.20-2.22), 1.02 (95% CI 0.01-4.30) and 0.78 (95% CI 0.07-2.58), respectively.
Risk for leukaemia was not associated with bone marrow dose (ERR/100mGy 0.21; 95% CI -0.12 to 2.40; P=.68).
“Our results indicate that the relatively high brain doses from head CT scans (20-50mGy) may increase brain tumour risk, whereas red bone marrow (RBM) doses generally under 10mGy per CT and often under 5mGy, do not lead to an observable risk increase,” the authors concluded.
They advise that although there are limitations to the study, the findings call for careful justification of paediatric CT scans and dose optimisation to minimise the risks.