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STAGING OF KIDNEY CANCER
Although grading and the identification of cancer cell types help determine a patient's prognosis, most doctors believe that the most important factor in predicting prognosis as well as the treatment options is the stage.
Staging is the process of gathering information from exams and diagnostic tests to determine the size of the tumor and how widespread a cancer is. Staging allows a physician to gauge the size and location of tumors by using information gathered from imaging studies such as CT scans and MRI’s, as well as from pathology tests and physical examinations.
Staging factors that influence a patient's prognosis are:
- Spread to tissues surrounding the kidney
- Spread to contiguous organs
- Spread to nearby lymph nodes (the small, bean-shaped structures found throughout the body that produce and store infection-fighting cells)
- Distant metastasis
The treatment and prognosis or outlook for RCC will depend significantly on its stage. There are two staging systems for RCC, the TNM System and the Robson.
TNM Staging System
The most commonly used staging system is that of the American Joint Committee on Cancer (AJCC), sometimes also known as the TNM system. The TNM (tumor-node-metastasis) system uses stages generally similar to those of the Robson system. This staging system is becoming more widely accepted because it provides a more detailed description of the tumor(s).
The letter T followed by a number from 0 to 3 describes the tumor's size and spread to nearby tissues. Some of these numbers are further subdivided with letters, such as T1a and T1b. 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 the body to fight infections and cancers.
The letter M followed by a 0 or 1 indicates whether or not the cancer has spread (metastasized) to other organs such as the lungs or bones, or to lymph nodes that are not near to the kidneys.
Primary Tumor Stage (T stage)
Graphic Representation
Description
T1
Tumor is confined to the kidney (i.e. no penetration through the capsule) and is 7 centimeters or less in greatest dimension
T2
Tumor is confined to the kidney (i.e. no penetration through the capsule) and is greater than 7 centimeters in greatest dimension
T3a
Tumor penetrates through the kidney capsule into the surrounding fat or the adrenal gland, but not through Gerota’s fascia.
T3b or T3c
Tumor extends into the renal vein or into the vena cava. (T3b indicates that the tumor thrombus does not extend above the level of the diaphragm. T3c indicates that the tumor thrombus extends above the level of the diaphragm)
T4
Tumor penetrates through Gerota’s fascia.
Regional Lymph Nodes (N stage)
Description
N0
No cancer in the lymph nodes
N1
Cancer in a single lymph node
N2
Cancer in more than one lymph node
Distant Metastasis
(M Stage)Description
M0
No metastasis
M1
Distant metastasis present
Summary of AJCC (TNM) Stages
Stage 1
T1,N0,M0
The tumor is 7 cm or smaller and limited to the kidney. There is no spread to lymph nodes or distant organs.
Stage 2
T2, N0, M0The tumor is larger than 7 cm but is still limited to the kidney. There is no spread to lymph nodes or distant organs.
Stage 3
T1a -T3b, N1, M0
or
T3a -T3c, N0, M0
There are several combinations of T and N categories that are included in this stage.
These include any tumor that has spread to 1 nearby lymph node but not to more than 1 lymph node or other organs.
Stage 3 also includes tumors that have not spread to lymph nodes or distant organs but have spread to the adrenal glands, to fatty tissue around the kidney, and/or have grown into the large vein (vena cava) leading from the kidney to the heart.
Stage 4
T4
Any T, N2
Or
Any T, Any N, M1
There are several combinations of T, N, and M categories that are included in this stage.
This stage includes any cancers that have spread directly through the fatty tissue and beyond Gerota fascia, the fibrous tissue that surrounds the kidney.
Stage 4 also includes any cancer that has spread to more than 1 lymph node near the kidney, or to any lymph node distant from the kidney, or to any distant organs such as the lungs, bone, or brain.
Survival by T Stage for Patients Treated with Surgery
T Stage Cancer
5 /10-Year Cancer-Specific Survival
(Only deaths due to kidney cancer)T1
95% / 91%
T2
80% / 70%
T3a
66% / 53%
T3b
52% / 43%
T3c
43% / 42%
Grading Scale for Kidney Cancer:
Another important factor used by doctors in their assessing renal cell carcinoma is its Fuhrman Grade (named after the pathologist who developed the system). This refers to how closely the cancer cells look like normal kidney cells under a microscope. Furhman grading systems grades tumor cells on a scale of 1 through 4. Grade 1 tumor cells being little different from normal kidney cells. These cancers usually grow and spread slowly and most often have a good prognosis. Grade 4 tumor cells look quite different from normal kidney cells and have a worse prognosis.
Although the cell type and grade are sometimes helpful in predicting a prognosis, the cancer's stage is by far the best predictor of survival. The stage describes the cancer's size and how far it has spread beyond the kidney. See “Staging of Kidney Cancer”
Recent data suggest that clear cell RCC has a slightly worse prognosis as compared to papillary or chromophobe cell RCC, however, the majority of low stage tumors, regardless of its cell type, can be cured with surgical resection. Oncocytoma is usually a benign lesion with an extremely low chance of spreading. Spindle cell types or sarcomas tend to grow and spread more quickly than the other kinds of RCCs. It can be associated with any of subtype mentioned and this subtype portends poor prognosis.
The University of California Los Angeles Integrated Staging System
This is a more complex but probably more accurate system that includes the stage, a person’s overall health, and the Fuhrman Grade of the tumor. Patients without any tumor spread are divided into 3 groups: low risk, intermediate risk, and high risk. The low-risk people are Stage I, in excellent health other than the cancer and have a low Fuhrman Grade tumor. The high-risk patients are either Stage III (but without lymph node spread) with poor health and a high Fuhrman score or Stage IV (without any spread, T4, N0, M0). The intermediate-risk group is all others, without any spread.
The 5-year cancer-specific survival (only deaths from cancer) for the low-risk group is 91%, for the intermediate-risk group is 80%, and for the high-risk group is 55%.
Patients with tumor spread, to lymph nodes or distance sites such as bone, lung, or liver, are also divided into these 3 groups. Low-risk patients have a tumor that is T1-3, N1, M0. High-risk patients have a T4 tumor, poor health and high Fuhrman Grade or distant spread. Intermediate grades are all others.
The 5-year cancer-specific survival (only deaths from cancer) is lower in these people whose tumors have spread: for the low-risk group it is 32%, for the intermediate-risk group 20% and for the high-risk group 0%.
For more information about our program please contact:
Nazy Zomorodian, MSN, CUNP
Director, GU Clinical Trials Office
(310) 794-7704
Fax: (310) 794-7787
nzomorodian@mednet.ucla.edu