Since sarcomas are complex and can develop in so many places in the body, they can be difficult to diagnose. However, it’s important to have an accurate diagnosis of the type and extent of the sarcoma before you are treated.
Getting the wrong diagnosis may actually be harmful and make therapy have less chance for success. A biopsy that is not done correctly can cause the cancer to spread and make your treatment more difficult. It is best for the surgeon who does the biopsy to also remove the tumor.
If at all possible, your first biopsy should be at the cancer center where you will receive treatment. Try to go to a cancer center that sees a large number of sarcoma patients and has a specialized sarcoma team that includes specialized pathologists.
If you have symptoms that may signal sarcoma, your doctor will examine you and ask you questions about your health and your family medical history.
Sarcoma Diagnostic Tests
The only way to be certain a tumor is sarcoma is a biopsy (removing a small number of cells to examine under a microscope). Imaging tests may be used before or after biopsy to determine the location and extent of the tumor.
The doctor will choose one of the following types of biopsy depending on where the tumor is.
Fine needle aspiration (FNA): A very small needle is placed into the tumor and suction is applied. CT (computed tomography) scans may be used to help guide the needle. Doctors trained to read these types of biopsies then review the small numbers of cells that are drawn into the needle.
If the test shows that the tumor may be a sarcoma, another type of biopsy probably will be done to remove a larger piece of tissue.
Core needle: The doctor uses a needle slightly larger than the one used in an FNA biopsy to remove a cylindrical sample of tissue.
Incisional: An incision (cut) is made in the skin and a small part of tumor is removed
Excisional: An incision (cut) is made in the skin and the entire growth is removed surgically
Imaging tests, which may include:
CT or CAT (computed axial tomography)
MRI (magnetic resonance imaging) scans
PET (positron emission tomography) scans
Research shows that many cancers can be prevented.
Soft Tissue Sarcoma Stages
If you are diagnosed with sarcoma, your doctor will determine the stage (or extent) of the disease.
The system often used to stage sarcomas is the TNM system of American Joint Committee on Cancer.
T stands for the size of the tumor.
N stands for spread to lymph nodes (small bean-shaped collections of immune system cells found throughout the body that help fight infections and cancers).
M is for metastasis (spread to distant organs).
In soft tissue sarcomas, an additional factor, called grade (G), is part of tumor stage. The grade is based on how the sarcoma cells look under the microscope.
The official staging system divides sarcomas into three grades (1 to 3). The grade of a sarcoma helps predict how rapidly it will grow and spread, as well as your outlook for successful treatment (prognosis). The grade is part of what is used to determine the stage of a sarcoma.
The grade of a sarcoma is based on the way the cancer looks under the microscope. In grading a cancer, the pathologist considers three factors:
How closely the tumor resembles normal tissue (differentiation) on a scale of 1 to 3
How many of the cells appear to be dividing, on a scale of 1 to 3 (mitotic count)
How much of the tumor is made up of dying tissue (tumor necrosis)
These factors are scored, and then the scores are added together to determine the grade of the tumor. The sarcomas with cells looking more normal and with fewer cells dividing are generally placed in a low-grade category. Low-grade tumors are slow growing, slower to spread and often have a better outlook (prognosis) than higher-grade tumors. The grade is usually based on the way the cells look and how many are dividing, but certain types of sarcoma are automatically given higher scores for differentiation. This affects the overall score so much that they are never considered to be low grade. Examples of these include synovial sarcoma and embryonal sarcoma.
The scores for each factor are added up 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 or higher
T1: The sarcoma is 5 cm (2 inches) or less across.
T1a: The tumor is superficial -- near the surface of the body.
T1b: The tumor is deep in the limb or abdomen.
T2: The sarcoma is greater than 5 cm across.
T2a: The tumor is superficial -- near the surface of the body.
T2b: The tumor is deep in the limb or abdomen.
N0: The sarcoma has not spread to nearby lymph nodes.
N1: The sarcoma has spread to nearby lymph nodes.
M0: No distant metastases (spread) of sarcoma are found.
M1: The sarcoma has spread to distant organs or tissues (such as the lungs).
Stage grouping for soft tissue sarcomas
To assign a stage, information about the tumor, its grade, lymph nodes, and metastasis is combined by a process called stage grouping. The stage is described by Roman numerals from I to IV with the letters A or B. The stage is useful in selecting treatment, but other factors, like where the sarcoma is located, also impact treatment planning and outlook.
T1, N0, M0, G1 or GX: The tumor is not larger than 5 cm (2 inches) across (T1). It has not spread to lymph nodes (N0) or more distant sites (M0). The cancer is grade 1 (or the grade cannot be assessed).
T2, N0, M0, G1 or GX: The tumor is larger than 5 cm (2 inches) across (T2). It has not spread to lymph nodes (N0) or more distant sites (M0). The cancer is grade 1 (or the grade cannot be assessed).
T1, N0, M0, G2 or G3: The tumor is not larger than 5 cm (2 inches) across (T1). It has not spread to lymph nodes (N0) or more distant sites (M0). The cancer is grade 2 or 3.
T2, N0, M0, G2: The tumor is larger than 5 cm (2 inches) across (T2). It has not spread to lymph nodes (N0) or more distant sites (M0). The cancer is grade 2.
Stage 3: Either
T2, N0, M0, G3: It is larger than 5 cm (2 inches) across (T2). It has not spread to lymph nodes (N0) or more distant sites (M0). The cancer is grade 3, OR
Any T, N1, M0, any G: The cancer can be any size (any T) and any grade. It has spread to nearby lymph nodes (N1). It has not spread to distant sites (M0).
Any G, Any T, Any N, M1: The tumor has spread to lymph nodes near the tumor (N1) and/or to distant sites (M1). It can be any size (any T) and grade (any G).
Staging is a way of determining how much disease is in the body and where it has spread. This information is important because it helps your doctor determine the best type of treatment for you and the outlook for your recovery (prognosis).
Once the staging classification is determined, the stage stays the same even if treatment is successful or the cancer spreads.