The Performance of Tumor Size as Risk Stratification Parameter in Upper Tract Urothelial Carcinoma (UTUC)

The objective of this study was to evaluate the performance of different tumor diameters for identifying ≥ pT2 upper tract urothelial carcinoma (UTUC) at radical nephroureterectomy.This was a multi-institutional retrospective study that included 932 patients who underwent radical nephroureterectomy for nonmetastatic UTUC between 2000 and 2016. Tumor sizes were pathologically assessed and categorized into 4 groups: ≤ 1 cm, 1.1 to 2 cm, 2.1 to 3 cm, and3 cm. We performed logistic regression and decision-curve analyses.Overall, 45 (4.8%) patients had a tumor size ≤ 1 cm, 141 (15.1%) between 1.1 and 2 cm, 247 (26.5%) between 2.1 and 3 cm, and 499 (53.5%)3 cm. In preoperative predictive models that were adjusted for the effects of standard clinicopathologic features, tumor diameters2 cm (odds ratio, 2.38; 95% confidence interval, 1.70-3.32; P .001) and3 cm (odds ratio, 1.81; 95% confidence interval, 1.38-2.38; P .001) were independently associated with ≥ pT2 pathologic staging. The addition of the2-cm diameter cutoff improved the area under the curve of the model from 58.8% to 63.0%. Decision-curve analyses demonstrated a clinical net benefit of 0.09 and a net reduction of 8 per 100 patients.The 2-cm cutoff appears to be most useful in identifying patients at risk of harboring ≥ pT2 UTUC. This confirms the current European Association of Urology guideline's risk stratification. Tumor size alone is not sufficient for optimal risk stratification, rather a constellation of features is needed to select the best candidate for kidney-sparing surgery.