Abstract
AimsThe European Association of Urology guideline for upper tract urothelial carcinoma (UTUC) relies on two grading system: 1973 World Health Organization (WHO) and 2004/2016 WHO. No consensus has been made which classification should supersede the other and both are recommended in clinical practice. We hypothesized that one may be superior to the other.MethodsNewly diagnosed non-metastatic UTUC patients treated with radical nephroureterectomy were abstracted from the Surveillance, Epidemiology, and End Results database (2010–2016). Kaplan–Meier plots and multivariable Cox regression models (CRMs) tested cancer-specific mortality (CSM), according to 1973 WHO (G1 vs. G2 vs. G3) or to 2004/2016 WHO (low-grade vs. high-grade) grading systems. Haegerty’s C-index quantified accuracy.ResultsOf 4271 patients, according to 1973 WHO grading system, 134 (3.1%) were G1, 436 (10.2%) were G2 and 3701 (86.7%) were G3; while according to 2004/2016 WHO grading system, 508 (11.9%) were low grade vs 3763 (88.1%) high grade. In multivariable CRMs, high grade predicted higher CSM (Hazard ratio: 1.70, p < 0.001). Conversely, neither G2 (p = 0.8) nor G3 (p = 0.1) were independent predictors of worse survival. The multivariable models without consideration of either grading system were 74% accurate in predicting 5-year CSM. Accuracy increased to 76% after either addition of the 1973 WHO or 2004/2016 WHO grade.ConclusionsFrom a statistical standpoint, either 1973 WHO or 2004/2016 WHO grading system improves the accuracy of CSM prediction to the same extent. In consequence, other considerations such as intra- and interobserver variability may represent additional metrics to consider in deciding which grading system is better.
Highlights
Variables definitionUpper tract urothelial carcinoma (UTUC) is a rare and aggressive malignancy, with an estimated annual incidence in Western Countries of almost two cases per 100,000 inhabitants [1] and with non-organ confined stage in two-third of newly diagnosed patients [2,3,4,5]
We examined the ability of either the 1973 or the 2004/2016 World Health Organization (WHO) grading system in predicting cancer-specific mortality (CSM), in a contemporary cohort of non-metastatic upper tract urothelial carcinoma (UTUC) patients treated with radical nephroureterectomy (RNU), identified within a large-scale database, namely the Surveillance, Epidemiology and End Results, from 2010 to 2016
Sensitivity analyses testing the effect of grade (1973 and 2004/2016 WHO grading systems) on CSM were performed in UTUC patients with T1 stage and in UTUC patients with T2 or lower stage
Summary
Variables definitionUpper tract urothelial carcinoma (UTUC) is a rare and aggressive malignancy, with an estimated annual incidence in Western Countries of almost two cases per 100,000 inhabitants [1] and with non-organ confined stage in two-third of newly diagnosed patients [2,3,4,5]. The most recent European Association of Urology (EAU) UTUC guideline relies and recommends the use of two different grading systems. These consist of the 1973 World Health Organization (WHO) and the 2004/2016 WHO classification. Since there is no consensus on which of the two grading systems should be used in everyday clinical practice [12, 15] and since both are recommended [2], we hypothesized that one may be better To test this hypothesis, we examined the ability of either the 1973 or the 2004/2016 WHO grading system in predicting CSM, in a contemporary cohort of non-metastatic UTUC patients treated with radical nephroureterectomy (RNU), identified within a large-scale database, namely the Surveillance, Epidemiology and End Results, from 2010 to 2016
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