Soft Tissue Sarcoma Stages
After someone is diagnosed with a soft tissue sarcoma, doctors will try to figure out if it has spread, and if so, how far. This process is called staging. The stage of a cancer describes how much cancer is in the body. It helps determine how serious the cancer is and how best to treat it. Doctors also use a cancer’s stage when talking about survival statistics.
The stages of soft tissue sarcomas range from stages I (1) through IV (4). As a rule, the lower the number, the less the cancer has spread. A higher number, such as stage IV, means cancer has spread more. And within a stage, an earlier letter means a lower stage. Although each person’s cancer experience is unique, cancers with similar stages tend to have a similar outlook and are often treated in much the same way.
How Is The Stage Determined?
The grade cannot be assessed (because of incomplete information).
Grade 1 (G1)
Total score of 2 or 3.
Grade 2 (G2)
Total score of 4 or 5
Total score of 6, 7 or 8
The staging system most often used for soft tissue sarcomas is the American Joint Committee on Cancer (AJCC) TNM system, which is based on 4 key pieces of information:
The extent of the tumor (T): How large is the cancer?
The spread to nearby lymph nodes (N): Has the cancer spread to nearby lymph nodes?
The spread (metastasis) to distant sites (M): Has the cancer spread to distant organs such as the lungs?
The grade (G) of the cancer: How much do the sarcoma cells look like normal cells?
The grade of a sarcoma is determined using a system known as the French or FNCLCC system, and is based on 3 factors:
Differentiation: Cancer cells are given a score of 1 to 3, with 1 being assigned when they look similar to normal cells and 3 being used when the cancer cells look very abnormal. Certain types of sarcoma are given a higher score automatically.
Mitotic count: How many cancer cells are seen dividing under the microscope; given a score from 1 to 3 (a lower score means fewer cells were seen dividing)
Tumor necrosis: How much of the tumor is made up of dying tissue; given a score from 0 to 2 (a lower score means there was less dying tissue present).
The scores for each factor are added to determine the grade for the cancer. Higher-grade cancers tend to grow and spread faster than lower-grade cancers.
GX: The grade cannot be assessed (because of incomplete information)
Grade 1 (G1): Total score of 2 or 3
Grade 2 (G2): Total score of 4 or 5
Grade 3 (G3): Total score of 6, 7 or 8
There are different staging systems for soft tissue sarcomas depending on where the cancer is in the body.
Head and neck
Trunk and extremities (arms and legs)
Abdomen and thoracic (chest) visceral organs
Numbers or letters after T, N, and M provide more details about each of these factors. Higher numbers mean the cancer is more advanced. Once a person’s T, N, and M categories have been determined, this information is combined in a process called stage grouping to assign an overall stage. Of the 4 main locations, only 2 (Trunk and Extremities and Retroperitoneum) have stage groupings. For more information see Cancer Staging.
The staging system in the table below uses the pathologic stage (also called the surgical stage). It is determined by examining tissue removed during an operation. Sometimes, if surgery is not possible right away or at all, the cancer will be given a clinical stage instead. This is based on the results of a physical exam, biopsy, and imaging tests. The clinical stage will be used to help plan treatment. Sometimes, though, the cancer has spread further than the clinical stage estimates, and may not predict the patient’s outlook as accurately as a pathologic stage.
The system described below is the most recent AJCC system, effective January 2018. Cancer staging can be complex, so ask your doctor to explain it to you in a way you understand.