Staging is a way of describing a cancer, such as where it is located, if or where it has spread, and if it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the cancer's stage, so staging may not be complete until all the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis (chance of recovery). There are different stage descriptions for different types of cancer.
One tool that doctors use to describe the stage is the TNM system. This system uses three criteria to judge the stage of the cancer: the tumor itself, the lymph nodes around the tumor, and if the tumor has spread to other parts of the body. The results are combined to determine the stage of cancer for each person. There are five stages: stage 0 (zero) and stages I through IV (one through four); stage 0 kidney cancer is extremely rare. The stage provides a common way of describing the cancer, so doctors can work together to plan the best treatments.
It is important for doctors to learn as much as possible about the tumor because this information can help them predict if the cancer will grow and spread or how it will respond to treatment. This information includes the cell type, the grade (describes how similar the cancer cells are to normal cells), the presence of certain proteins on the cancer cells, (such as carbonic anhydrase IX or HLA B7), and information from the patient (his or her activity level, weight loss, and the presence or absence of fevers and sweats, and other symptoms).
TNM is an abbreviation for tumor (T), node (N), and metastasis (M). Doctors look at these three factors to determine the stage of cancer:
- How large is the primary tumor and where is it located? (Tumor, T)
- Has the tumor spread to the lymph nodes? (Node, N)
- Has the cancer metastasized to other parts of the body? (Metastasis, M)
Tumor. Using the TNM system, the "T" plus a letter or number (0 to 4) is used to describe the size and location of the tumor. Some stages are also divided into smaller groups that help describe the tumor in even more detail. This helps the doctor develop the best treatment plan for each patient. If there is more than one tumor, the lowercase letter "m" (multiple) is added to the "T" stage category. Specific tumor stage information for kidney cancer is listed below.
TX: The primary tumor cannot be evaluated.
T0: There is no evidence of a primary tumor in the kidney(s).
T1: The tumor is found only in the kidney and is 7 centimeters (cm) or smaller in size at its greatest dimension (its largest area). There has been much discussion among doctors whether this classification should only include a tumor 5 cm and under.
T1a: The tumor is found only in the kidney and is 4 cm or smaller in size at its largest area.
T1b: The tumor is found only in the kidney and is between 4 cm and 7 cm at its largest area.
T2: The tumor is found only in the kidney and is larger than 7 cm in size at its largest area.
T3: The tumor has grown into major veins or it has spread to the adrenal gland (gland on top of each kidney that produces hormones and adrenaline to help control heart rate, blood pressure, and other body functions) or perinephric tissue (connective, fatty tissue around the kidneys). It has not grown beyond Gerota's fascia (an envelope of tissue that surrounds the kidney).
T3a: The tumor has spread to the adrenal gland or perinephric tissue, but the tumor has not grown beyond Gerota's fascia.
T3b: The tumor has grown into the renal vein(s) (the large vein leading out of the kidney) or vena cava (the large vein leading out of the heart) below the diaphragm (the muscle under the lungs that helps breathing).
T3c: The tumor has grown into the renal vein(s) or vena cava above the diaphragm.
T4: The tumor has spread to areas beyond Gerota's fascia.
Node. The “N” in the TNM staging system stands for lymph nodes, the tiny, bean-shaped organs that help fight infection. Lymph nodes near the kidneys are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes.
NX: The regional lymph nodes cannot be evaluated.
N0: The cancer has not spread to the regional lymph nodes.
N1: The cancer has spread to a single regional lymph node area.
N2: The cancer has spread to more than one regional lymph node area.
Distant metastasis. The "M" in the TNM system indicates whether the cancer has spread to other parts of the body. Common areas where kidney cancer may spread include the bones, liver, lungs, brain, and distant lymph nodes.
MX: Distant metastasis cannot be evaluated.
M0: The disease has not metastasized.
M1: There is distant metastasis (the cancer has spread to other parts of the body beyond the kidney area).
Cancer stage grouping
Doctors assign the stage of the cancer by combining the T, N, and M classifications.
Stage I: The tumor is 7 cm or smaller and is in the kidney only. It has not spread to the lymph nodes or distant organs of the body (T1, N0, M0).
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Stage II: The tumor is larger than 7 cm and is in the kidney only. It has not spread to the lymph nodes or distant organs of the body (T2, N0, M0).
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Stage III: Either of these conditions:
- The tumor has spread to one nearby lymph node, but not distant lymph nodes or other organs (T1, T2, T3; N1; M0).
- The tumor has spread to fatty tissue around the kidney and/or has spread into the renal vein, but has not spread to any lymph nodes or other organs (T1, T2, T3; N0; M0).
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Stage IV: Any of these conditions:
- The tumor has spread directly through the fatty tissue and the fascia, possibly to lymph nodes, but not to other parts of the body (T4; N0, N1; M0).
- The tumor has spread to more than one lymph node area near the kidney, but not to other parts of the body (any T, N2, M0).
- The tumor has spread to any other organ, such as the lungs, bones, or the brain (any T, any N, M1).
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Recurrent: Recurrent cancer is cancer that comes back after treatment. It may be found in the kidney area or in another part of the body.
Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Sixth Edition (2002) published by Springer-Verlag New York, www.springer-ny.com.
Last Updated: December 30, 2008
