Cancer staging is a term used to refer to describing the tumor's size and whether or not it has spread beyond the area where it began.

• TNM staging

This is the most commonly used staging system for kidney cancer.

- T gives the size of the tumor.

- N refers to whether or not there has been lymph node involvement.

- M indicates whether the cancer has spread to other parts of the body (metastatic).

T- Tumor

T1: The cancer is no bigger than 7 cm and is located inside the kidney.

T1A: The cancer is not bigger than 4 cm and is located in the innermost part of the kidney.

T1B: T1A: The cancer is 4-7 cm big and is located in the innermost part of the kidney.

T2: The cancer is bigger than 7 cm and is located inside the kidney.

T2A: The cancer is 7-10 cm big and is located in the innermost part of the kidney.

T2B: The cancer is bigger than 10 cm and is located inside the kidney.

T3: The cancer has spread to the fat that surrounds the kidney though not beyond the fibrous tissue (Gerota's fascia); or the cancer has already spread into the primary veins that surround the kidney (the vena cava and renal vein).

T3A: The cancer has spread into the renal vein or the fat surrounding the kidneys but not into the fibrous tissues (Gerota's fascia).

T3B: The cancer has spread to the part located below the diaphragm of the vena cava.

T3C: The cancer has spread into the vena cava above the diaphragm and is growing along the wall of the blood vessel.

T4: The cancer has spread beyond the fibrous tissue (Gerota's fascia) that surrounds the kidney.

N- Nodes

This is a description of whether the cancer has spread to the lymph nodes located near the kidney.

N0: No cancer cells in the lymph nodes.

N1 - There are cancer cells in 1 or more lymph nodes.

If the cancer cells have spread to the lymph nodes, the nodes are said to be positive.

M – Metastases

M0 - The cancer cells have not spread to other parts of the body.

M1 - The cancer cells have spread to other parts of the body.

If the kidney cancer spreads, it is most likely to spread into the bones, lungs, kidney, or brain. If the cancer has spread, it is called metastatic cancer.

• Numeric staging

Stages T, N, and M can be grouped together to give an overall stage for the cancer.

Stage 1: The cancer is 7 cm big or less and is located inside the kidney. It has not spread to the lymph nodes or other organs.

Stage 2: The cancer is bigger than 7 cm and is located inside the kidney. It has not spread to the lymph nodes or other organs.

Stage 3: The cancer is located only in the lining of the stomach (mucosa) and has spread to 1 or more lymph nodes.

The can has started to spread outside of the kidney and may have reached one of the main veins located in the vicinity of the kidney (vena cava). Or it has spread into the fat that surround the kidney. It may have spread into the lymph nodes.

Stage 4: The cancer has spread to other parts of the body. It can be of any size and may have grown into tissues located outside of the kidney.

GRADING

Grading refers to the appearance of the cancer cells under the microscope. This classification provides information on how the cancer cells can behave.

The Fuhrman system is the most commonly used staging system for kidney cancer. It goes from 1 to 4 based on how abnormal the cells are.

Grade-1 cancer usually grows slowly and is less likely to spread than cancers of higher grades, such as grade-4 cancer.