Validation of 2009 TNM classification based on a prognostic analysis of 350 patients treated for renal cell carcinoma

PURPOSE: To validate 2009 TNM classification (7th edition) of renal cell carcinoma (RCC), we reevaluated our RCC database depends on 6th and 7th TNM staging and analyzed a prognostic divergence between subgroups. METHODS: A study population of 350 patients with RCC was retrospectively reviewed based on the TNM classification both 6th and 7th editions. Cause-specific survival (CSS) in each group was estimated using Kaplan-Meier method. RESULTS: Applying the new TNM system, 336 patients were divided into pT1a 131, pT1b 105, pT2a 31, pT2b 13, pT3 a 38, pT3b 3, pT3c 0, pT4 14. Previously pT3b-staged 11 cases with renal vein involvement without vena caval extension were included into pT3a. Due to the positive direct invasion into the adrenal gland, previously pT3-staged six patients were changed to pT4. Kaplan-Meier curves revealed no significant differences in CSS between each a/b subgroups from pT1 to pT3. Particularly, no significant statistical value was recognized between pT2a and pT2b subgroups. Patients with direct adrenal invasion tended to show a less favorable prognosis than those with invasion beyond Gerota. CONCLUSIONS: (1) pT2 subdivision does not affect prognostic value. (2) Population imbalance is enhanced due to the pT 3 reclassification. (3) Direct adrenal invasion is compatible with pT4 category.