pT3 subclassification of renal pelvic cancer considering the tumor location improves the patients’ prognostic accuracy

Whether pT3 urothelial carcinoma of the renal pelvis (UCRP) and urothelial carcinoma of the ureter (UCU) have the same prognosis is controversial, this study compared the prognosis of pT3 UCRP with that of pT3 UCU. We retrospectively evaluated 954 patients who underwent nephroureterectomy at our institutions between January 1983 and December 2017. All surgical specimens were reviewed by a single genitourinary pathologist. Cases of pT3 UCRP were subclassified as pT3a (urothelial carcinomas extending only to the renal medulla) and pT3b (urothelial carcinomas extending into the renal cortex and/or peripelvic adipose tissue). Fine and Gray’s model was used to predict recurrence-free survival (RFS) and cancer-specific survival (CSS). A total of 493 (51.7%) had UCRP and 461 (48.3%) had UCU. Within this group, 202 patients had pT3 UCRP and 146 had pT3 UCU. The pT3 subclassification of UCRP resulted in 79 cases of pT3a and 120 of pT3b. The difference in 5-year CSS among the pT3a UCRP, pT2 UCRP, and pT2 UCU subgroups was not statistically significant (pT3a UCRP vs pT2 UCRP, HR = 0.69, p = 0.56; pT3a UCRP vs pT2 UCU, HR = 0.66, p = 0.31) However, RFS and CSS were significantly higher in the pT3a UCRP group than in the pT3b group (pT3a vs pT3b, HR = 2.59, p = 0.0038 and pT3a vs pT3b, HR = 3.10, p = 0.001). The results suggest that our proposed pT3 subclassification better predicts the prognosis of UCRP patients than does the pT3 of the current AJCC/UICC classification.