UTUC, as mentioned before, is a rare disease with low prevalence. It rarely presents with hematuria; hematuria evaluations often are associated with (in order of decreasing incidence): normal urinary tracts, bladder cancer, urolithiasis, renal cell carcinoma, UTUC (0.1-2.2% prevalence). As part of his thesis work, he found that UTUC was more common in women, and in older patients. UTUC also usually presents as small flat tumors, making imaging difficult.
False positives in the imaging diagnostics of UTUC are high, often leading to need for biopsy. The positive predictive value of CT urogram is between 57-90% in most series, and unfortunately, over diagnoses UTUC.
Urologist and Radiologist:
He emphasized the need to work together to help address the question of optimum diagnostic strategy. Specifically, which tests to order, what sequence to order them in, and its effect on management and outcomes. Avoid the 3C’s: Cliches, Conflicts of Interest, Convention. Basically, all specialties should acknowledge their limitations, forget about prior biases and question the current standards.
The components that need to be considered in coming up with a strategy are: diagnostic accuracy, patient acceptability, availability, and cost/reimbursement policies. Diagnostic accuracy, cost, and disease prevalence are difficult to overlap effectively.
Optimum patient journey:
Presentation Risk Stratification Diagnostic test (hopefully just 1) Treatment
In UTUC: Presentation Risk Stratification CT Urogram Biopsy
Risk stratification for hematuria should take into account available clinical/family history, urine cytology, prior imaging, and co-existing urothelial cancer history.
- Don’t do all tests in one patient!
- Goal: Reduce cost and reduce time to diagnosis
Goals for radiology: optimizing imaging technique, interpretation, reporting, diagnostic accuracy. Key to this is standardization!
One of the highlights of the talk was his discussion on CT Urography. Current tri-phasic CT has three key phases: Non-contrast, nephrogram phase (50-100 seconds), excretory phase (750 sec).
However, there are actually 7 distinct phases for CT Urography that may be used. There is a urothelial phase (30-50 seconds) that may be the most useful and most accurate. Its diagnostic accuracy (sensitivity, specificity, PPV, NPV) matches CT Urography (including excretory phase).
He also noted that completing CT Urography during the expiratory phase are superior to inspiration as it straightens out the upper urinary tract.
Presented by: Nigel Cowan
Written by: Thenappan Chandrasekar, MD Clinical Fellow, University of Toronto, twitter: @tchandra_uromd at the 2018 European Association of Urology Meeting EAU18, 16-20 March, 2018 Copenhagen, Denmark