['The clinical course of pT3 upper tract urothelial carcinoma (UTUC) is highly variable.', 'The aim of the current study was to validate the clinical and prognostic importance of pT3 subclassification in the renal pelvicalyceal system in a large international cohort of patients.', 'From a multi-institutional international database, 858 renal pelvicalyceal tumors treated with radical nephroureterectomy (RNU) were systematically reevaluated by genitourinary pathologists. Category pT3 pelvic tumors were categorized as pT3a (infiltration of the renal parenchyma on a microscopic level only) versus pT3b (macroscopic infiltration of the renal parenchyma and/or infiltration of peripelvic adipose tissue).', 'RNU.', 'Associations of pT3 subclassifications with clinicopathologic features were assessed with the chi-square test. Prognostic impact was assessed with the log-rank test and multivariable Cox regression analyses.'] Is subclassification of pT3 urothelial carcinoma of the renal pelvicalyceal system associated with recurrence-free and cancer-specific survival : proposal for a revision of the current TNM classification?