Renal cancer, also referred to as kidney cancer, is a disease where cancer cells develop in your kidneys.
Like other types of cancer, renal cancer is staged based on how large and far the condition has grown. Identifying the stage of cancer is needed because deciding the most effective treatment often depends on it.
The most common system that is used to stage renal cancer is the "TNM" system.
The "T" Stages of Kidney Cancer
T stands for tumor. This portion identifies the size of the main tumor and whether it has grown into surrounding areas. The T stages include:
T0
There is no evidence of a tumor in the kidney
T1
There is a tumor, but is no more than 7 cm across and it is found completely inside the kidney. There are also two subsets of T1 tumors:
- T1a: tumor is smaller than 4 cm.
- T1b: tumor is between 4 cm and 7cm across.
T2
The tumor is larger than 7 cm across but is still only in the kidney. As with T1, T2 tumors are broken down even further:
- T2a: The tumor is bigger than 7 cm, but not bigger than 10 cm across and is found completely within the kidney.
- T2b: The tumor is bigger than 10 cm across and is still only in the kidney
T3
The tumor is growing into a major vein or into tissue surrounding the kidney, but it is not growing into the adrenal gland, which is on top of the kidney or beyond Gerota’s fascia—which is the fibrous layer that surrounds the kidney and surrounding fatty tissue. Its subtypes include:
- T3a: The tumor is growing into a main vein outside of the kidney, renal vein, or into fatty tissue surrounding the kidney
- T3b: The tumor is growing into the part the large vein that leads into the heart, the vena cava.
- T3c: The tumor has grown into the part of the vena cava that is located within the chest or it is growing into the wall of the vena cava.
T4
The cancer has spread beyond the tissues around the kidney.
The "N" Stages of Kidney Cancer
N stands for lymph nodes. If the cancer is classified as this, then the cancer has spread to your lymph nodes. Lymph nodes are a small collection of immune system cells, and they are usually where cancer spreads first. There are three lymph node stages in kidney cancer. They include:
- N0: No cancer in any lymph nodes
- N1: Cancer has spread to only one nearby lymph node
- N2: Cancer spread to more than one nearby lymph node
Lymph nodes that contain cancer are called positive lymph nodes. The lymph nodes that are closest to the kidney are the para aortic, renal hilar, and caval lymph nodes.
The "M" Stages of Kidney Cancer
M stands for metastases, which means the cancer has spread to other parts of the body. The most common areas being the lungs, bones, liver, brain and distant lymph nodes. There are two stages for metastases:
- M0: the cancer has not spread
- M1: the cancer has spread and you have advanced cancer
Number Stages
After the TNM stages have been identified, the stage is then combined with an overall number stage I, II, III, or IV. Lower stages tend to have a better outlook.
