Validation of the 2009 TNM version in a large multi-institutional cohort of patients treated for renal cell carcinoma: are further improvements needed?

A new edition of the TNM was recently released that includes modifications for the staging system of kidney cancers. Specifically, T2 cancers were subclassified into T2a and T2b (< or =10 cm vs >10 cm), tumors with renal vein involvement or perinephric fat involvement were classified as T3a cancers, and those with adrenal involvement were classified as T4 cancers. OBJECTIVE: Our aim was to validate the recently released edition of the TNM staging system for primary tumor classification in kidney cancer. DESIGN, SETTING, AND PARTICIPANTS: Our multicenter retrospective study consisted of 5339 patients treated in 16 academic Italian centers. INTERVENTION: Patients underwent either radical or partial nephrectomy. MEASUREMENTS: Univariable and multivariable Cox regression models addressed cancer-specific survival (CSS) after surgery. RESULTS AND LIMITATIONS: In the study, 1897 patients (35.5%) were classified as pT1a, 1453 (27%) as pT1b, 437 (8%) as pT2a, 153 (3%) as pT2b, 1059 (20%) a