title: Subsequent cancer risk of children receiving post voiding cystourethrography: a nationwide population-based retrospective cohort study.
abstract: BACKGROUND
  To estimate the subsequent cancer risk of children receiving post voiding cystourethrography (VCUG), a nationwide population-based retrospective cohort study with the data from the Taiwan National Health Insurance Research Database (NHIRD) were used for the analysis.
  
  
  METHODS
  In the VCUG cohort, 31,908 participants younger than 18 years of age who underwent VCUG between 1997 and 2008 were identified from the NHIRD. A comparison cohort, the non-VCUG cohort, was randomly selected among children without VCUG examination histories during 1997-2008, frequency matched for age (every 5 years), sex, geographic region area, parents' occupation, and index year based on a 1:4 ratio. Cox's proportional hazard regression analysis was conducted to estimate the subsequent cancer risk of children receiving VCUG.
  
  
  RESULTS
  The overall cancer risk of the VCUG cohort is 1.92-fold (95 % CI = 1.34-2.74) higher than that of the non-VCUG cohort with statistical significance. The genital cancer and urinary system cancer risks of the VCUG cohort are respectively 6.19-fold (95 % CI = 1.37-28.0) and 5.8-fold (95 % CI = 1.54-21.9) higher than those of the non-VCUG cohort with statistical significance. The hazard ratios are higher in genital cancer, urinary system cancer (the major radiation exposure area), and cancer of the abdomen, except for the genitourinary system (the minor radiation exposure area), in sequence.
  
  
  CONCLUSIONS
  Pediatric VCUG is associated with increased subsequent cancer risk, especially in the genitourinary system.
authors.affiliation: Department of Radiology, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Yen-Hsiu
authors.initials: YH
authors.lastname: Liao
authors.forename: Cheng-Li
authors.initials: CL
authors.lastname: Lin
authors.forename: Chang-Ching
authors.initials: CC
authors.lastname: Wei
authors.forename: Po-Pang
authors.initials: PP
authors.lastname: Tsai
authors.forename: Wu-Chung
authors.initials: WC
authors.lastname: Shen
authors.forename: Fung-Chang
authors.initials: FC
authors.lastname: Sung
authors.forename: Tsai-Chung
authors.initials: TC
authors.lastname: Li
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Kao
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009369:Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000401:mortality; D012189:Retrospective Studies; D012306:Risk; D012737:Sex Factors; D012959:Socioeconomic Factors; D016019:Survival Analysis; D013624:Taiwan / Q000453:epidemiology; D014567:Urography / Q000009:adverse effects*; D014718:Vesico-Ureteral Reflux / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000453:epidemiology*