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 researchers are trying to find out more.

Certain things that can affect the chances of developing a soft tissue sarcoma. These are called risk factors. Having a risk factor does not mean you will get sarcoma, and people without risk factors can still develop it.


Sarcoma can develop at any age, but the risk increases as you get older.

Genetic conditions

Most sarcoma is 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 with certain rare inherited genetic conditions are more at risk of developing a sarcoma. These include:

  • neurofibromatosis – a genetic disorder that causes tumours to form on nerve tissue
  • retinoblastoma – a rare eye cancer that develops in young children
  • Li-Fraumeni syndrome – linked with an increased risk of developing several types of cancer, including soft tissue sarcoma
  • familial adenomatous polyposis (FAP) – causes large numbers of polyps in the bowel.

If you have one of these genetic conditions, you will probably already know. Your doctor can tell you about any symptoms of sarcoma that you need to be aware of.

A family with a strong history of lots of different types of cancer, such as breast and bowel cancer, may have an increased risk of soft tissue sarcoma. If you are worried about your family history of cancer, talk to your GP. If needed, they can refer you to a genetic clinic for testing.

Previous radiotherapy treatment

Rarely, a soft tissue sarcoma develops in a part of the body that has been treated with radiotherapy for another type of cancer. The sarcoma does not usually develop until at least 5 to 10 years after radiotherapy. To reduce this risk, radiotherapy is planned very carefully. The risk of developing a sarcoma afterwards is very small.


Long-term swelling in an arm or leg is called lymphoedema. It can increase the risk of developing an angiosarcoma. Lymphoedema can develop if the lymph nodes are removed or damaged. For example, lymphoedema may develop in:

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

Exposure to chemicals

Being exposed to a chemical called vinyl chloride may increase the risk of angiosarcoma. This chemical is used for making plastic. Other chemicals such as pesticides and benzenes have been linked with sarcoma, but the evidence for this is weak.


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.

About our information

  • References

    Below is a sample of the sources used in our soft tissue sarcoma information. If you would like more information about the sources we use, please contact us at

    Gronchi A, Miah AB et al. Soft tissue and visceral sarcomas: ESMO-EURACAN-GENTURIS Clinical practice guidelines for diagnosis, treatment and follow-up. Annals of Oncology, 2021; 32, 11, 1348-1365 [accessed May 2022].

    Casali PG, Blay JY et al. Gastrointestinal stromal tumours: ESMO-EURACAN-GENTURIS Clinical practice guidelines for diagnosis, treatment and follow-up. Annals of Oncology, 2022; 33,1, 20-33 [accessed May 2022].

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by senior medical editor Fiona Cowie, Consultant Clinical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

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Date reviewed

Reviewed: 01 August 2022
Next review: 01 August 2025
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

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