ON THIS PAGE: You will learn about how doctors describe a tumor’s growth or spread, as well as the way the sarcoma cells look when viewed under a microscope. This is called the stage and grade. To see other pages, use the menu on the side of your screen.
Staging is a way of describing where the tumor is located, if or where it has spread, and whether it is affecting other parts of the body. Doctors use diagnostic tests to find out a sarcoma'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, which is the 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. TNM is an abbreviation for tumor (T), node (N), and metastasis (M). Doctors look at these three factors to determine the stage of a tumor:
- 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 tumor metastasized to other parts of the body? (Metastasis, M)
When staging sarcoma, another factor, grade (G), is added to the TNM system. This is different from staging for many other types of cancer.
The results are combined to determine the stage for each person. There are five stages: stage 0 (zero) and stages I through IV (one through four). The stage provides a common way of describing the tumor, so doctors can work together to plan the best treatments.
Here are more details on each part of the TNM system for soft tissue sarcoma. This staging system applies to all types of soft tissue sarcoma except Kaposi sarcoma, gastrointestinal stromal tumor (GIST), and infantile fibrosarcoma. Also excluded from this staging system are sarcomas that begin in the central nervous system, including the brain or the lining around the brain and spinal cord, and sarcomas that begin in an organ or a hollow organ, such as the bowel or urinary tract.
Tumor. Using the TNM system, the "T" plus a number (0 to 2) and letter (a or b) is used to describe the size and location of the tumor. The tumor (T) is further described by its depth. The tumor depth is described as either superficial or deep. Superficial means the tumor is above the body's superficial tissue. Deep means the tumor is either beneath the body's superficial tissue or invades the deep tissue. Specific tumor stage information is listed below.
TX: The primary tumor cannot be evaluated.
T0: There is no evidence of a primary tumor.
T1: The size of the tumor is 5 centimeters (cm) or smaller.
T1a: The tumor is superficial.
T1b: The tumor is deep.
T2: The size of the tumor is larger than 5 cm.
T2a: The tumor is superficial.
T2b: The tumor is deep.
Node. The “N” in the TNM staging system stands for lymph nodes, tiny, bean-shaped organs that help fight infection. Each type of tumor drains into nearby lymph nodes, called regional lymph nodes. Sarcoma rarely spreads to the 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 the regional lymph nodes.
Distant metastasis. The "M" in the TNM system indicates if the cancer has spread to other parts of the body.
M0: The cancer has not metastasized.
M1: There has been metastasis to another part of the body.
Doctors also describe this type of cancer by its grade (G). The grade for sarcoma describes how likely a tumor is to grow and spread. A tumor's grade is described using the letter “G” and a number. There are four grades for sarcoma: GX (the grade cannot be evaluated), G1, G2, and G3. The grade is determined by calculating a score based on the following factors:
- How different the cancer cells look compared to healthy tissue cells when viewed under a microscope.
- How many tumor cells are dividing.
- How much of the tumor has cells that are dying.
The lower the combined score for these three factors, the lower the grade, meaning that the tumor is less aggressive and a patient’s prognosis is better. This is the recommended grading system but others may also be used. For instance, some doctors grade sarcomas as either “low grade” or “high grade,” particularly if the tumor has been treated before surgery.
Doctors assign the stage of the cancer by combining the T, N, M, and G classifications. For sarcoma, stages I and II are described in smaller groups according to the tumor's depth.
Stage IA: The tumor is 5 cm or smaller in size and either superficial or deep. It has not spread to the lymph nodes or to other parts of the body (T1a or T1b, N0, M0, GX or G1).
Stage IB: The tumor is larger than 5 cm in size and either superficial or deep. It has not spread to the lymph nodes or to other parts of the body (T2a or T2b, N0, M0, GX or G1).
Stage IIA: The tumor is 5 cm or smaller in size and either superficial or deep. It has not spread to the lymph nodes or to other parts of the body. The grade is higher than the grade for stage IA (T1a or T1b, N0, M0, G2 or G3).
Stage IIB: The tumor is larger than 5 cm in size and either superficial or deep. It has not spread to the lymph nodes or to other parts of the body. The grade is higher than the grade for stage IB (T2a or T2b, N0, M0, G2).
Stage III: This stage can be described by either of the following:
- The tumor is larger than 5 cm in size and either superficial or deep. It has not spread to the lymph nodes or to other parts of the body. The grade is higher than the grade for stage IIB (T2a or T2b, N0, M0, G3).
- The tumor is any size, either superficial or deep, or any grade. However, it has spread to the regional lymph nodes but not to other parts of the body (any T, N1, M0, any G).
Stage IV: The tumor is any size, either superficial or deep, any grade, and may or may not have spread to the regional lymph nodes. However, it has spread to other parts of the body (any T, any N, M1, and any G).
Recurrent: Recurrent sarcoma is sarcoma that has come back after treatment. If there is a recurrence, the sarcoma may need to be staged again (called re-staging) using the system above.
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, Seventh Edition (2010) published by Springer-Verlag New York, www.cancerstaging.net.
Information about the tumor’s stage will help the doctor recommend a treatment plan. The next section helps explain the treatment options for sarcoma. Use the menu on the side of your screen to select Treatment Options, or you can select another section, to continue reading this guide.