The process of finding out how far the cancer has spread iscalled staging. In sarcoma staging, doctors also evaluate the appearance of the tumor under the microscope and judge how fast the cancer seems to be growing. The stage of a sarcoma is the most significant factor in determining each patient's prognosis (the course of the disease and the chances of survival) and in selecting treatment options.

The information needed to stage sarcomas includes biopsies, imaging tests of the main tumor (usually with CT or MRI scans), and imaging tests of other parts of the body where the cancer may have spread.

When examining the biopsy sample, the pathologist (doctor who specializes in diagnosing diseases by looking at the tissue under a microscope) takes into account the number of cells that are actively dividing and how closely the cancer resembles normal tissue. He or she determines the cell type and grade and estimates how rapidly it will grow and spread.

A staging system is a standard way for the cancer care team to summarize the extent of a cancer's spread. 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 also part of tumor stage. The grade is based on how the sarcoma cells look under the microscope.

Grade

This is a sign of how likely it is the cancer will spread. Previously, grade was only based on how normal the cells looked at under the microscope (called differentiation). This was not very helpful, and under a new system (known as the French or FNCLCC system), grade is based on 3 factors:

• Differentiation -- on a scale of 1 to 3
• Mitotic count -- how many cancer cells are seen dividing (under the microscope) -- given a score from 1 to 3
• Tumor necrosis -- how much of the tumor is made up of dying tissue -- given a score from zero to 2.

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

Tumor

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.

Lymph nodes

N0: The sarcoma has not spread to nearby lymph nodes.

N1: The sarcoma has spread to nearby lymph nodes.

Metastasis

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. Although stage is useful in selecting treatment, other factors, such as where the sarcoma is located, also impact treatment planning and outlook.

Stage IA: 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).

Stage IB: 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).

Stage IIA: 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.

Stage IIB: 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 III: 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).

Stage IV: 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).

Although this staging system is useful in selecting treatment, other factors, such as where the sarcoma is located, also impact treatment planning and outlook.

Survival by stage

Survival depends on many factors, including the stage and location of the tumor, the type of sarcoma, and the age of the patient. For example, sarcomas of the arms or legs have a better outlook than those found in other places. Also, older patients tend to have worse outcomes than younger people.

Also, the following numbers discuss 5-year survival. The 5-year survival rate refers to the percentage of patients who live at least 5 years after their cancer is diagnosed. Many people live more than 5 years, but 5-year rates are used to produce a standard way to discuss outlook for survival. Five-year relative survival rates assume that some people will die of other causes and compare the observed survival with that expected for people without the cancer. This is a more accurate way to look at deaths from a particular type and stage of cancer.

The overall 5-year relative survival of people with soft tissue sarcomas is around 50% according to statistics from the National Cancer Institute (NCI). These statistics include people with Kaposi sarcoma, which has a poorer outlook than many sarcomas. The NCI doesn't separate cases into the AJCC staging system. Instead, they group sarcomas only by whether they are still confined to the primary site (called localized) have spread to regional lymph nodes or directly beyond the primary site (called regional); or have metastasized (called distant). The corresponding 5-year relative survival rates were:

• 83% for localized sarcomas (56% of soft tissue sarcomas were localized when they were diagnosed)
• 54% for regional stage sarcomas; (19% were in this stage)
• 16% for sarcomas with distant spread (16% were in this stage)

The 10-year relative survival rate is only slightly worse for these stages, meaning that most people who survive 5 years are cured.

For specific AJCC stages the 5-year survival, according to data from Memorial Sloan-Kettering Cancer Center published in the AJCC Cancer Staging Manual only for sarcomas of the arms or legs is:

Survival is worse when the sarcoma has developed somewhere other than the arms or legs. For example, the 5-year survival for retroperitoneal sarcomas is around 40% to 60%.

The 5-year survival rates for soft tissue sarcomas have not changed much for many years.

Last Medical Review: 03/03/2009
Last Revised: 05/14/2009