Peripelvic/periureteral fat invasion is independently associated with worse prognosis in pT3 upper tract urothelial carcinoma.

PURPOSE: To elucidate the reasons for conflicting results regarding the prognostic significance of tumor location in upper tract urothelial carcinoma (UTUC), we analyzed the stage-specific impact of tumor location on oncological outcomes following radical nephroureterectomy (RNU).
METHODS: Data from 392 patients who underwent RNU with curative intent between 1991 and 2010 were reviewed. Prognostic impact of tumor location and various clinicopathological factors for recurrence-free survival (RFS) and cancer-specific survival (CSS) was evaluated using Kaplan-Meier and Cox regression analyses at each pathological stage. Tumor location was classified as renal pelvis or ureter, and pT3 tumors were further stratified as invading the renal parenchyma or peripelvic or periureteral fat.
RESULTS: In stage-specific analysis, tumor location did not have prognostic significance in patients with ≤pT2 tumors, whereas RFS and CSS rates were significantly lower in patients with pT3 ureteral tumors than renal pelvic tumors. Subgroup analysis showed that RFS and CSS rates were significantly higher for pT3 tumors invading the renal parenchyma than the peripelvic or periureteral fat. On multivariate analysis in pT3 tumors adjusting other clinicopathological parameters, tumor location remained significant predictors for both RFS and CSS. Compared with tumors invading renal parenchyma, tumors invading peripelvic fat or periureteral fat were associated with about 3.5 times higher risk for cancer-specific mortality (p < 0.05).
CONCLUSIONS: Location-dependent survival difference exists only in patients with pT3 UTUC. Conflicting institutional results regarding tumor location in UTUC may be due to difference in the proportions of parenchymal versus peripelvic fat invasion in pT3 pelvic tumors.