Risk scoring system for evaluating pathological upstaging after radical nephroureterectomy for upper tract urothelial carcinoma: A multicenter study in Japan

Objectives: Accurate preoperative staging of upper tract urothelial carcinoma is often difficult. Therefore, we aimed to investigate the preoperative factors associated with pathological upstaging in patients with upper tract urothelial carcinoma undergoing radical nephroureterectomy and to develop a risk-scoring system to assess pathological upstaging. Methods: This retrospective study enrolled 386 patients with upper tract urothelial carcinoma who underwent radical nephroureterectomy at Tottori University Hospital and affiliated hospitals between January 2015 and December 2021. Patients with clinical tumor stage 4, clinical node +, and those who received neoadjuvant chemotherapy were excluded from the study. The association between preoperative patient factors and pathological upstaging was analyzed. Statistical analyses included the t-test, chi-squared test, and logistic regression analysis. Results: Of the 386 patients, 32 were excluded. Finally, 354 patients were included in this study, of whom 87 (24.6%) were pathologically upstaged. Hydronephrosis, positive urine cytology result, and maximum tumor diameter <30 mm were associated with upstaging. We developed a risk scoring system in which the score was the sum of the number of applicable items for three factors: hydronephrosis, positive urine cytology result, and maximum tumor size <30 mm. The probabilities of ureteral cancer upstaging were 0%, 8.3%, 29.5%, and 50.0% for scores of 0, 1, 2, and 3, respectively. Conclusions: Hydronephrosis, urine cytology, and maximum tumor diameter were associated with pathological upstaging. Our risk-scoring system may be useful in predicting pathological upstaging, especially in patients with ureteral cancer.