Soft tissue sarcomas can develop anywhere in the body but is more common in the thigh, shoulder and pelvis. There are more than 70 different types of soft tissue sarcomas.

Soft tissue sarcomas develop in the connective tissues that connect and support the body including muscle, fat, nerves, tendons, lining of joints, lymph vessels or blood vessels.

The stages of soft tissue sarcomas are classified by the TNM system, which stands for:

• Tumour (T) – describes the size of the tumour and the extent the cancer has spread. The tumour can be graded from T1 (describing a tumour 5cm or less) to T2 (greater than 5cm).  The letter ‘a’ is used to describe a tumour that is near the surface of the body while ‘b’ indicates that it is deeper in the body.
• Nodes (N) – describes whether the tumour has spread to nearby lymph nodes. Nodes can be graded from N0, where there has been no spread, through to N1, where the cancer has spread the lymph nodes.
• Metastasis (M) – describes whether the cancer has spread to other areas of the body. Metastasis can be graded from M0, where there has been no spread through to M1, where the cancer has spread to other organs of the body and produced additional tumours.

Soft tissue sarcomas are also given a grade (G) from G1 to G3. Soft tissue sarcomas with a higher grade are more aggressive and have a higher likelihood of growing and spreading faster that those with a lower grade.

The TNM ratings are used in combination with the grade to determine the stage of the soft tissue sarcoma.