Staging is the process of determining how far the cancer has spread. A standardized system was defined by the American Joint Committee on Cancer (AJCC) known as the TNM system and describes 3 key pieces of information:
T – indicates the size of the main tumor and has it grown into nearby areas. Within this category, the following letters and numbers are defined:
- T0 – No evidence of a primary tumor.
- T1a – The tumor is 4cm or less and only in the kidney.
- T1b – The tumor is between 4 cm and 7 cm and is only in the kidney.
- T2a – The tumor is between 7cm and 10 cm and is only in one kidney.
- T2b – The tumor is larger than 10cm and only in the kidney.
- T3a – The tumor is growing into a main vein (renal vein) leading out of the kidney or into the fatty tissue around the kidney.
- T3b – The tumor is growing into the part of the large vein leading into the heart (vena cava)that is within the abdomen.
- T3c – The tumor has grown into the part of the vena cava that is within the chest or into the wall of the vena cava.
- T4 – The tumor has spread beyond Gerota’s fascia and may have grown into the adrenal gland.
M – describes the extent of the spread to nearby lymph nodes.
N – indicates if the cancer has metastasized (spread) to other organs.