The most important factor in predicting prognosis is the stage. The stage describes the cancer's size and how deeply it has spread beyond the kidney. The Staging System of the American Joint Committee on Cancer (AJCC) is sometimes known as TNM system. The letter T followed by a number from 1 to 3 describes the tumor's size and spread to nearby tissues. Higher T numbers indicate a larger tumor and/or more extensive spread to tissues near the kidney. The letter N followed by a number from 0 to 2 indicates whether the cancer has spread to lymph nodes near the kidney and, if so, how many are affected. Lymph nodes are bean-sized collections of immune system cells that help fight infections and cancers. The letter M followed by a 0 or 1 indicates whether or not the cancer has spread to distant organs (for example, the lungs or bones) or to lymph nodes that are not near to the kidneys. The next section summarizes features of the 1997 revision of AJCC stages for cancer. Summary of renal cell cancer AJCC (TNM) stages

Stage I: The tumor is 7 cm (about 2 3/4 inches) or smaller, and limited to the kidney. There is no spread to lymph nodes or distant organs.
Stage II: The tumor is larger than 7.0 cm but still limited to the kidney. There is no spread to lymph nodes or distant organs.
Stage III: There are several combinations of T and N categories that are included in this stage. These include tumors of any size, with or without spread to fatty tissue around the kidney, with or without spread into the large veins leading from the kidney to the heart, with spread to one nearby lymph node, but without spread to distant lymph node or other organs. Stage III also includes tumors with spread to fatty tissue around the kidney and/or spread into the large veins leading from the kidney to the heart, that have not spread to any lymph nodes or other organs.

Stage IV: There are several combinations of T, N, and M categories that included in this stage. This stage includes any cancers that have spread directly through the fatty tissue and the fascia ligament-like tissue that surrounds the kidney. Stage IV also includes any cancer that has spread to more than one lymph node near the kidney, to any lymph node not near the kidney, or to any other organs such as the lungs, bone, or brain. Detailed definitions of renal cell cancer T, N, M categories and stage groupings

Primary tumor (T):

TX: Primary tumor cannot be assessed
T0: No evidence of primary tumor
T1: Tumor 7 cm or less, limited to kidney
T2: Tumor greater than 7 cm, limited to kidney
T3: Tumor extends into major veins/adrenal/ perinephric tissue; not beyond Gerota's fascia
T3a: Tumor invades adrenal/perinephric fat
T3b: Tumor extends into renal vein(s) or vena cava below diaphragm
T3c: Tumor extends into vena cava above diaphragm
T4: Tumor invades beyond Gerota's fascia

N - Regional lymph nodes
NX: Regional nodes cannot be assessed
N0: No regional lymph node metastasis
N1: Metastasis in a single regional lymph node
N2: Metastasis in more than one regional lymph node

M - Distant metastasis
MX: Distant metastasis cannot be assessed
M0: No distant metastasis
M1: Distant metastasis