The further tests already described help to find the stage and the grade of the cancer. These help the doctors to decide on the most appropriate treatment.

Grading refers to the appearance of the cancer cells under the microscope. The grade gives an idea of how quickly the cancer may develop. Grading of soft tissue sarcomas can sometimes be difficult, especially for the less common types. There are four grades, from 1 to 4.

• Grade 1 means that the cancer cells look very like the normal cells of the soft tissues (called well-differentiated). They are usually slow-growing and are less likely to spread.
• Grade 2 means the cancer cells have begun to look more abnormal. They are described as being moderately differentiated.
• Grade 3 soft tissue sarcomas are described as being poorly differentiated – the cancer cells look very abnormal, are likely to grow quickly, and are more likely to spread.
• Grade 4 soft tissue sarcomas are either poorly differentiated or undifferentiated. Undifferentiated cancer cells are primitive and immature. They don’t function properly and have no specific appearance. Grade 4 soft tissue sarcomas are likely to grow more quickly and are more likely to spread.

The stage of a cancer describes its size and whether it has spread beyond its original area of the body.

Several different staging systems may be used for soft tissue sarcomas. A commonly used staging system, produced by the American Joint Committee on Cancer (AJCC), is described below and includes information about the grade of the cancer as well as the stage:

There are four major stages (from 1 to 4).

• Stage 1 The cancer is low-grade (grades 1 or 2) and can either be close to the surface of the body (superficial) or deep within the body. There is no sign of any spread.
• Stage 2 The cancer is high grade (grades 3 or 4). It is either superficial or deep within the body, but has not spread to lymph nodes or other parts of the body.
• Stage 3 The cancer is described as high-grade, large (5cm or bigger) and deep. It has not begun to spread.
• Stage 4 The cancer can be any grade, but it has spread to lymph nodes in the area or to any other part of the body, such as the lungs, head or neck. This is known as secondary cancer (or metastatic cancer).

Recurrence means that a soft tissue sarcoma has come back after it was first treated. It may come back in the area where it first started, or it may come back in another part of the body.

TNM staging system

Another staging system known as the TNM system is also commonly used. This can give your doctors more precise information about the extent of the cancer.

• T describes the size of the tumour.
• N describes whether the cancer has spread to the lymph nodes.
• M describes whether the cancer has spread to another part of the body (secondary or metastatic cancer).