TNM staging of kidney cancer in AJCC 2009: Primary tumor (T): TX Primary tumor could not be evaluated; T0 No primary tumor found; T1 Tumor confined to the kidney, maximum diameter ≤ 7cm; T1a, tumor confined to the kidney, maximum tumor diameter ≤ 4cm; T1b, tumor confined to the kidney, 4cm < maximum tumor diameter ≤ 7cm T2 Tumor confined to the kidney, maximum diameter > 7cm T2a, 7cm < maximum tumor diameter ≤ 10cm; T2b, tumor confined to the kidney, maximum tumor diameter > 10cm T3, tumor invading renal vein or perirenal tissue other than ipsilateral adrenal gland, but not exceeding perirenal fascia; T3a, tumor invading renal vein or invading renal segmental vein (or vein of muscle layer) or perirenal adipose tissue and/or sinus adipose tissue of renal vein branches, but not exceeding T3b Tumor invades the inferior vena cava below the diaphragm; T3c Tumor invades the inferior vena cava above the diaphragm or invades the wall of the inferior vena cava. T4 Tumor infiltration beyond the perinephric fascia, including invasion of the ipsilateral adrenal gland adjacent to the tumor. Regional lymph nodes (N): Nx regional lymph node metastasis cannot be assessed; N0 no regional lymph node metastasis; N1 single regional lymph node metastasis; N2 more than one regional lymph node metastasis; Distant metastasis (M): MX distant metastasis cannot be assessed; M0 no distant metastasis; M1 distant metastasis; Regional lymph nodes in the kidney include: hilar lymph nodes, periventricular lymph nodes, periaortic lymph nodes and perirenal retroperitoneal lymph nodes.