Evaluation of the Risks and Benefits of Computed Tomography Urography for Assessment of Gross Hematuria

To model the risk of radiation-induced malignancy from computed tomography urography (CTU) in evaluation of gross hematuria and contrast this with the benefits of urinary tract cancer detection when compared to renal ultrasound.

A PUBMED-based literature search was performed to identify model inputs. Estimates of radiation-induced malignancy rates were obtained from the Biological Effects of Ionizing Radiation VII report with dose extrapolation using the linear no-threshold model.

Male gender and age over 50 years were associated with a relative risk of upper tract malignancy of 2.04 and 2.95, respectively. The risk of upper tract malignancy missed by renal ultrasound ranged from 0.055% in females under 50 to 0.51% in males over 50. Risk of CTU-induced malignancy with associated loss of life expectancy ranged from 0.25% and 0.027 years in females under 50 to 0.08% and 0.0054 years in males over 50. For CTU to be superior to renal ultrasound, an undiagnosed upper tract malignancy would have to carry a loss of life expectancy of 49.2 years in females under 50, 13.4 years in males under 50, 2.6 years in females over 50, and 1.1 years in males over 50.

In low-risk patients, CTU for evaluation of gross hematuria may carry a significant risk of radiation-induced secondary malignancy relative to the diagnostic benefit offered over renal ultrasound.