What is soft tissue sarcoma?

Soft tissue sarcoma is a cancer that develops in the supporting tissues in the body. These include:

  • fat
  • muscle
  • blood vessels
  • deep skin tissues
  • nerves
  • tendons and ligaments
  • the tissues around the joints (synovial tissues)
Diagram of the soft tissue in the body

Together, these tissues are known as connective tissues. They connect, support or surround other structures or organs in the body.

The bones are also a supporting tissue. There are different types of sarcoma that affect the bones. These can be treated differently.

Where do soft tissue sarcomas grow?

Soft tissue is in all parts of the body. So soft tissue sarcomas can develop and grow almost anywhere. If a sarcoma is not treated, the cells continue to divide and the sarcoma will grow in size.

The growth of the sarcoma causes a lump in the soft tissues. This can cause pressure on any body tissues or organs nearby.

Over time, sarcoma cells from the original area may break away. If the cells get into the bloodstream they can spread to other areas of the body. These cells can then form new areas of sarcoma, which are known as secondary cancers or metastases.

Sarcomas most commonly spread to the lungs. Sometimes they may spread to the bones.

Types of soft tissue sarcoma

There are many different types of soft tissue sarcoma. The type depends on the type of cell that the cancer started in.

Who gets soft tissue sarcoma?

Soft tissue sarcoma is most common in older people. But compared to most other cancer types, it is also quite common in younger people. In the UK, an average of around 40 out of 100 (40%) of cases are diagnosed in people aged 65 years and over. But almost 10 in 100 (10%) are diagnosed in people younger than 30.

We don’t know what causes most soft tissue sarcoma cancers. But there are some factors that may increase your risk of developing it. Having any of these risk factors does not mean that you will definitely develop cancer. 

How common is soft tissue sarcoma?

Soft tissue sarcomas are rare cancers. Around 3,300 people are diagnosed with soft tissue sarcoma each year in the UK. That’s around 9 cases diagnosed every day. The number of people diagnosed with soft tissue sarcoma has increased since the late 1990s.