CANCER RISK IN CHILDREN CANCER RISK IN CHILDREN EXPOSED TO CT SCANSEXPOSED TO CT SCANS
Allison Low3.10.2013
Clinical Question• Do CT scans in children and adolescents increase
their subsequent risk of developing cancer?• P - children and adolescents• I - CT scans• C - no CT scans• O - cancer
Clinical cases• 13 year old boy with an incidental finding of
papilloedema, neurological examination otherwise normal
• 4 year old girl, RTA, GCS of 9, visible head injury, no external abdominal injuries, haemodynamically stable
Current practice
Methods• population based, cohort, data linkage study• Australia• 10.9 million people aged 0-19 (Medicare) over a 20
year period ending in 2005• monitoring until 2007
Methods• Medicare records record all (funded) CT scans• Australian Cancer Database (ICD-10 codes)• socioeconomic status from SEIFA
Methods - missed scans• state-based tertiary hospitals (not on records)• scans outside of Australia
Analysis• one year lag period (also five and ten year lags)• IRRs exposed vs unexposed• dosage: estimate by site, year of scan, age (changed
after 2001)
Results
Scans in exposed patients
Results• mean length of follow up: 17.3 years (unexposed), 9.5
years (exposed)• 3150 exposed individuals developed cancer• 57 524 non-exposed developed cancer• overall, IRR 24% higher in exposed group (IRR 1.24,
95% CI 1.20-1.29)
Main results
Other results• IRR increased with each additional CT scan (0.16 ,
95% CI 0.13-0.19)• IRR increased for all cancers combined, also for all
solid organ cancers, all lymphoid and haematopoeitic cancers
• site-specific eg leukaemia after CT abdo/pelvis• gender difference for non-brain solid organ tumours:
F>M (1.23)• socioeconomic status: no significant difference
Brain cancer• brain cancer - highest risk 1-4 years after exposure,
higher risk for 15 years• under five years riskiest• ? reverse causation - analysis repeated excluding all
brain cancers after CT brain - 1.20, 95% CI 1.15-1.24
CASP tool
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Discussion points• (no trauma CT patients with subsequent leukaemia in
Sheffield...)• Image Gently/ALARA• CT scans vs clinical skill