Preoperative predictors of nonorgan-confined disease in upper-tract urothelial carcinoma differ between China and the United States

Objective: To compare preoperative predictors of nonorgan-confined (NOC) disease in patients with upper-tract urothelial carcinoma (UTUC) from the United States (US) and China. Methods: Clinicopathologic data of patients with UTUC treated surgically at tertiary care facilities in the US or China from 1998 to 2015 were, retrospectively, compiled. Patient characteristics, preoperative imaging, cytology, ureteroscopic findings, and serum markers (neutrophil-to-lymphocyte ratio, estimated glomerular filtration rate, hemoglobin, and albumin) were evaluated. After excluding patients who received neoadjuvant chemotherapy, rates of NOC disease at definitive surgery were tabulated. Logistic regression and receiver operating characteristic analyses were performed to determine predictors of NOC for each country using previously published nomograms, and the cohorts were compared. Results: Totally, 753 patients with UTUC were included for analysis (451 Chinese and 302 US). NOC rates were similar between the 2 countries (31% vs. 29%, P = 0.568). On multivariable analysis, cT3 stage (P = 0.001) and high-grade pathology on ureteroscopy (P = 0.011) were significant predictors for NOC in the US, while male gender (P = 0.034), tumor location on imaging (P = 0.009), tumor size on imaging (P = 0.044), neutrophil-to-lymphocyte (P = 0.043), and preoperative estimated glomerular filtration rate (P = 0.028) were significant in China. Areas under the curve differed by nomogram used (Western model: 0.750 in US, vs. 0.670 in China; Chinese model: 0.763 in US, vs. 0.828 in China). Conclusion: Predictors for NOC in UTUC differ between the US and China. There may be unique population-based markers that more profoundly influence the accuracy of nomograms in certain populations. Our findings highlight the importance of considering population differences when clinically applying predictive tools in UTUC.