Role of CT urography in the clinical evaluation of upper tract urothelial carcinoma (of interest to Lynch Syndrome patients)

Blogger's note: this paper does not deal with genetics, note also that MRI is useful in UTUC

open access

Abstract

Intravenous urography has been widely used for the evaluation of upper tract urothelial carcinoma. However, computed tomography urography presently has a higher diagnostic accuracy for upper tract urothelial carcinoma (94.2–99.6%) than intravenous urography (80.8–84.9%), and has replaced intravenous urography as the first-line imaging test for investigating patients with a high risk of upper tract urothelial carcinoma. Although the detection rate for bladder tumors using standard computed tomography urography is not yet high enough to replace cystoscopy, the addition of a 60- to 80-s delayed scan after the administration of contrast material for the whole pelvis improves the detection rate. A drawback to computed tomography urography is the higher radiation dose of 15–35 mSv, compared with a mean effective dose of 5–10 mSv for intravenous urography. Among several approaches to reducing the radiation dose, the use of an iterative reconstruction algorithm is most likely to become an effective solution because of its simplicity. One advantage of computed tomography urography over intravenous urography is its ability to reliably differentiate between upper tract urothelial carcinoma and calculi or blood clots. Computed tomography urography also shows characteristic findings of other benign conditions. These findings, in combination with negative cytology, are very important diagnostic clues for avoiding an unnecessary nephroureterectomy. For the clinical staging, a recent study has reported the high diagnostic accuracy of computed tomography urography with respect to ≥pT3 tumors. The present review shows the current status of computed tomography urography for the evaluation of upper tract urothelial carcinoma.

Introduction

Tumors of the renal pelvis and ureter are rare, and account for just 8% of all urinary tract neoplasms; of these, more than 90% are urothelial carcinomas.[1] The incidence of these tumors is 0.7–1.1 per 100 000, and has increased slightly.[1] Recently, several advances have been made in the treatment of UTUC. Developments in endoscopic management have enabled less invasive therapy for small, low-grade, Ta or T1 UTUC,[2, 3] whereas neoadjuvant chemotherapy and lymph node dissection have improved the prognostic outcomes for muscle-invasive or locally advanced UTUC.[4-8] These developments have, more than ever, emphasized the importance of earlier detection and accurate UTUC staging using imaging modalities. Furthermore, considering that 8.5–13% of patients with UTUC have synchronous bladder cancer and 15–50% of patients with UTUC will develop bladder cancer, the need for non-invasive bladder surveillance at the initial examination or at follow-up examinations of these patients should be underscored.[9].....