Pretreatment Risk Stratification for Endoscopic Kidney-sparing Surgery in Upper Tract Urothelial Carcinoma: An International Collaborative Study

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BackgroundSeveral groups have proposed features to identify low-risk patients who may benefit from endoscopic kidney-sparing surgery in upper tract urothelial carcinoma (UTUC). ObjectiveTo evaluate standard risk stratification features, develop an optimal model to identify ≥pT2/N+ stage at radical nephroureterectomy (RNU), and compare it with the existing unvalidated models. Design, setting, and participantsThis was a collaborative retrospective study that included 1214 patients who underwent ureterorenoscopy with biopsy followed by RNU for nonmetastatic UTUC between 2000 and 2017. Outcome measurements and statistical analysisWe performed multiple imputation of chained equations for missing data and multivariable logistic regression analysis with a stepwise selection algorithm to create the optimal predictive model. The area under the curve and a decision curve analysis were used to compare the models. Results and limitationsOverall, 659 (54.3%) and 555 (45.7%) patients had ≤pT1N0/Nx and ≥pT2/N+ disease, respectively. In the multivariable logistic regression analysis of our model, age (odds ratio [OR] 1.02, 95% confidence interval [CI] 1.0–1.03, p = 0.013), high-grade biopsy (OR 1.81, 95% CI 1.37–2.40, p < 0.001), biopsy cT1+ staging (OR 3.23, 95% CI 1.93–5.41, p < 0.001), preoperative hydronephrosis (OR 1.37 95% CI 1.04–1.80, p = 0.024), tumor size (OR 1.09, 95% CI 1.01–1.17, p = 0.029), invasion on imaging (OR 5.10, 95% CI 3.32–7.81, p < 0.001), and sessile architecture (OR 2.31, 95% CI 1.58–3.36, p < 0.001) were significantly associated with ≥pT2/pN+ disease. Compared with the existing models, our model had the highest performance accuracy (75% vs 66–71%) and an additional clinical net reduction (four per 100 patients). ConclusionsOur proposed risk-stratification model predicts the risk of harboring ≥pT2/N+ UTUC with reliable accuracy and a clinical net benefit outperforming the current risk-stratification models. Patient summaryWe developed a risk stratification model to better identify patients for endoscopic kidney-sparing surgery in upper tract urothelial carcinoma.