Reassessment of Prognostic Heterogeneity of pT3 Renal Pelvic Urothelial Carcinoma: Analysis in Terms of Proposed pT3 Subclassification Systems

PurposeWe determined whether the 3 pT3 subclassification systems reported by the Asan, Cornell and Nagoya groups provide an accurate estimation of patient prognosis. We also determined which subclassification is most predictive of the heterogeneous oncological outcomes of pT3 renal pelvic urothelial carcinoma.Materials and MethodsUsing a Korea-Japan multi-institutional, retrospective database 250 pT3 renal pelvic urothelial carcinomas treated with radical nephroureterectomy were assigned to the 3 pT3 subcategories by tumor location and depth of parenchymal invasion after pathological reevaluation. Recurrence-free and cancer specific survival was assessed according to the 3 pT3 subclassifications. Predictive accuracy for survival in 4 models (baseline and each of the 3 pT3 subclassifications) was quantified and predictive accuracy increments for each model were compared.ResultsIn the baseline multivariate Cox regression model nodal metastasis and high grade were significant for survival. On multivariate analysis including the pT3 subclassifications the 3 subclassifications remained significantly associated with survival rates. Of the 3 pT3 subclassification systems the Cornell subclassification had the highest predictive accuracy for discriminating the heterogeneous prognosis of pT3 renal pelvic urothelial carcinoma, followed by the Nagoya subclassification. Compared with the baseline model adding the Cornell subclassification significantly increased predictive accuracy for recurrence-free survival from 0.687 to 0.742 (p = 0.029) and for cancer specific survival from 0.713 to 0.758 (p = 0.047).ConclusionsThe criteria of microscopic vs macroscopic parenchymal invasion and/or peripelvic fat invasion provide the most accurate differential classification of the prognostic heterogeneity of pT3 renal pelvic urothelial carcinoma. Further studies should be performed to determine the need to modify the current pT3 renal pelvic urothelial carcinoma staging system.