Soft tissue sarcoma risk factors: who is more likely to get it

What soft tissue sarcoma is

Soft tissues connect, support and surround other body parts and organs. They include muscles, tendons, fat, blood vessels, lymph vessels, nerves, fibrous tissue and the tissues around joints. Soft tissue sarcoma forms when cancer cells grow in these tissues (NCI PDQ).

It can form almost anywhere in the body, but NCI says it is most common in the arms, legs, abdomen and retroperitoneum (the back of the abdomen). There are many types, named for the kind of soft tissue the cancer started in (NCI PDQ). MedlinePlus says these cancers are not common (MedlinePlus).

Who is more likely to get soft tissue sarcoma

MedlinePlus says no one knows exactly what causes these cancers (MedlinePlus). NCI names these risk factors (NCI PDQ):

• Certain inherited disorders. NCI lists Li-Fraumeni syndrome (TP53 gene), neurofibromatosis type 1 (von Recklinghausen disease, NF1 gene), Gardner syndrome (APC gene), nevoid basal cell carcinoma syndrome (Gorlin syndrome, PTCH1 gene), tuberous sclerosis (TSC1 or TSC2 gene) and Werner syndrome (adult progeria, WRN gene) (NCI PDQ).
• Past radiation therapy. Having been treated with radiation therapy in the past raises the risk (NCI PDQ).
• Long-lasting lymphedema. Having lymphedema (swelling from fluid that the lymph system does not drain) in the arms or legs for a long time (NCI PDQ).
• Certain chemicals. Exposure to chemicals such as Thorotrast (thorium dioxide), vinyl chloride or arsenic (NCI PDQ).
• HIV and human herpesvirus 8. NCI says these viruses have been linked to Kaposi sarcoma, a separate type with its own NCI summary (NCI PDQ).

MedlinePlus gives the same three main groups: exposure to certain chemicals, past radiation therapy and certain genetic diseases (MedlinePlus). NCI adds that not every person with one or more risk factors will get soft tissue sarcoma, and that it also develops in people with no known risk factors. Talk with your doctor if you think you may be at risk (NCI PDQ).

Signs to check with a doctor

The main sign is a lump or swelling in soft tissue. It is often painless and often on an arm or a leg. Sarcomas that start in the abdomen may cause no signs until they are very big. As a sarcoma grows and presses on nearby organs, nerves, muscles or blood vessels, it can cause pain or trouble breathing (NCI PDQ). NCI says other conditions may cause the same signs, so check with your doctor if you have any of them (NCI PDQ).

How it is diagnosed

Doctors diagnose soft tissue sarcoma with a biopsy (MedlinePlus). NCI describes a core needle biopsy (several tissue samples taken with a wide needle, sometimes guided by ultrasound, CT or MRI) or an incisional biopsy (removing part of the lump). Because this cancer can be hard to diagnose, NCI says the samples should be checked by a pathologist with experience in soft tissue sarcoma (NCI PDQ).

Lowering the risk

Neither source lists a proven way to prevent soft tissue sarcoma. Most of the named risk factors, such as inherited disorders and past radiation therapy, cannot be changed. If one of the inherited disorders above runs in your family, NCI's advice is to talk with your doctor about your risk (NCI PDQ). Some of the same syndromes also raise the risk of other cancers; see our brain tumor risk factors and leukemia risk factors guides.

Common questions

Is soft tissue sarcoma the same as bone cancer?

No. Soft tissue sarcoma forms in soft tissues such as muscle, fat, nerves and blood vessels (NCI PDQ). This guide covers soft tissue sarcoma only.

Does a lump mean I have a sarcoma?

No. NCI says other conditions may cause the same signs (NCI PDQ), and MedlinePlus says these cancers are not common (MedlinePlus). NCI's advice is still to check with your doctor if you have a lump or swelling.

Can radiation for another cancer cause sarcoma later?

NCI lists past treatment with radiation therapy as a risk factor (NCI PDQ). NCI says not every person with a risk factor will develop soft tissue sarcoma (NCI PDQ). Ask the team that treated you which follow-up checks they suggest.