Staging and grading soft tissue sarcomas

Grading

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. 

In the UK, three grades (grades 1–3) are used for soft tissue sarcomas.

Low grade or grade 1 means that the cancer cells look very like normal cells of the soft tissues. They are usually slow-growing and are less likely to spread.

In high-grade or grade 3 cancers, the cells look very abnormal, are likely to grow quickly, and are more likely to spread.

Moderate-grade or grade 2 cancers fall between these two grades and have a level of activity somewhere in between.

Staging

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. The following stages are based on the staging system produced jointly by the American Joint Committee on Cancer (AJCC) and International Union against Cancer (UICC) but using the UK grading system.

There are four major stages from 1–4.

All stage 1 soft tissue cancers have not spread to lymph nodes or other parts of the body.

• Stage 1A The cancer is low or moderate (grade 1–2) and small (5cm or less). It can either be close to the surface of the body (superficial) or deep within the body.
• Stage 1B The cancer is low or moderate-grade (grade 1–2) and is larger than 5cm and close to the surface of the body (superficial).

All stage 2 soft tissue cancers have not spread to lymph nodes or other parts of the body. 

• Stage 2A The cancer is low, or moderate-grade and is larger than 5cm and deep within the body.
• Stage 2B The cancer is high-grade (grade 3), not larger than 5cm and superficial or deep within the body.
• Stage 2C The cancer is high-grade, larger than 5cm but superficial.

Stage 3 The cancer is high-grade, bigger than 5cm and is deep. It has not begun to spread.

Stage 4 The cancer can be any grade (grade 1–3), any size, superficial or deep, but it has spread to lymph nodes in the area or to any other part of the body, such as the lungs, liver, bones or soft tissues. This is known as secondary cancer or metastatic.