Subsequent cancer risk of children receiving post voiding cystourethrography: A nationwide population-based retrospective cohort study

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. 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. 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. Pediatric VCUG is associated with increased subsequent cancer risk, especially in the genitourinary system.