Causes of soft tissue sarcoma

The causes of soft tissue sarcomas are not known, but there are certain things that can affect the chances of developing it. These are called risk factors.

About causes and risk factors

The causes of soft tissue sarcomas are not known, but research is happening to try to find out more.

There are certain things that can affect the chances of developing a soft tissue sarcoma. These are called risk factors.

Having a risk factor does not necessarily mean you will get sarcoma, and people without risk factors can still develop it.

If you are worried about soft tissue sarcoma and would like to talk to someone, we're here. You can:


Sarcomas can develop at any age, but the risk increases as you get older. Some types of sarcoma can develop in children, teenagers and young adults. But they are more likely to develop in people over the age of 30.

Genetic conditions

Most sarcomas are not caused by an inherited faulty gene that can be passed on to other family members. Members of your family are not likely to have an increased risk of developing a soft tissue sarcoma because you have one.

But people who have certain rare inherited genetic conditions are more at risk of developing a sarcoma. These conditions include:

  • neurofibromatosis
  • retinoblastoma
  • Li-Fraumeni syndrome.

You normally know if you have one of these genetic conditions. Your doctor can tell you about any symptoms of sarcoma that you need to look out for.

Your family might have a strong history of lots of different types of cancer, such as breast and bowel cancer. Research has shown that this may mean you may have an increased risk of developing a soft tissue sarcoma.

Previous radiotherapy treatment

Very rarely, a soft tissue sarcoma develops in a part of the body that has previously been treated with radiotherapy for another type of cancer.

The sarcoma does not usually develop until at least 5 to 10 years after the radiotherapy treatment. To reduce this risk, radiotherapy is very carefully planned.

Improvements in the way radiotherapy is given mean the risk of developing a sarcoma after having it is very small.


Long-term swelling in an arm or leg, called lymphoedema, can increase the risk of developing a type of soft tissue sarcoma called angiosarcoma.

Lymphoedema can develop if the lymph nodes are removed or damaged. For example, it can develop:

  • in an arm, after surgery and radiotherapy for breast cancer
  • in a leg, after radiotherapy or surgery to the pelvic area.

Exposure to chemicals

The development of some sarcomas may be linked to exposure to some types of chemical. These include:

  • vinyl chloride – this is used for making plastics
  • some types of weed killer (herbicide)
  • dioxins – these are waste products made during the manufacture of chemicals and fertilisers.


There is no strong evidence that an injury can cause a soft tissue sarcoma to develop. It is possible that an injury may draw attention to a sarcoma that was already there, but not causing any symptoms.