Updated on April 3, 2024.
Soft tissue sarcoma (STS) is cancer that begins in the soft tissues of the body, such as fat tissue, muscles, nerves, connective tissue (which connects and supports organs and other parts of the body) and tissues of the digestive tract. Below are five basic facts about STS that will help give you an overview of the disease, including how it is diagnosed and how it is treated.
There are many different subtypes
There are more than 50 different subtypes of soft tissue sarcoma, and nearly any soft tissue in the body can be affected. Some subtypes are more common than others. The most common subtype in adults is liposarcoma, which begins in adipose (fat) tissue and accounts for roughly one in five cases of STS. Rhabdomyosarcoma, which affects the muscles attached to bones, is the most common form of STS in children.
Many people have no symptoms
In many cases, people with soft tissue sarcoma do not have any symptoms other than a noticeable lump that can be felt beneath the skin. These lumps can go unnoticed until the tumor grows in size and causes pain and/or inflammation, or affects functioning of the part of the body where it is located. Soft tissue sarcomas located in the digestive tract (called gastrointestinal stromal tumor or GIST) may cause symptoms such as abdominal pain, nausea, vomiting, blood in the stool(poop) or vomit, bowel obstruction (blockage) and anemia (tiredness due to low blood cell count as a result of bleeding in the digestive tract).
Diagnosis can be a challenge
Diagnosis of soft tissue sarcoma typically involves a combination of imaging tests (such as x-rays, MRIs, ultrasounds and others) and biopsy, where a sample of a tumor is taken, either using a needle or during surgery. Imaging tests can tell healthcare providers a lot about the size, location and appearance of the tumors. Biopsy and laboratory testing of the tissue samples is done to identify the subtype of soft tissue sarcoma. In some cases, the diagnosis is "uncertain type" of STS, which means testing shows that the cancer is STS but cannot determine the subtype.
Causes and risk factors are mostly unknown
Research has found several risk factors (things that increase the chances of developing a medical condition) for soft tissue sarcoma, which include genetic conditions, having received radiation therapy (high dose x-rays) for treatment of another cancer and exposure to certain chemicals. Some subtypes are more common in older adults, but others affect people of all ages, including younger adults and children. But for most people with STS, there is no identifiable cause.
Only one subtype of STS has a known cause—Kaposi sarcoma, which is caused by infection with a virus known as human herpesvirus 8 (HHV8) or a virus known as Kaposi sarcoma associated herpesvirus (KSHV). Kaposi sarcoma causes tumors underneath the surface of the skin and throughout the body.
Treatment usually involves surgery
Surgery is the most often used method of treatment for most types of soft tissue sarcoma. In cases where tumors are small and localized (meaning they are confined to a single location in the body), surgery may be the only treatment that is needed. In other cases, surgery will be used in combination with radiation therapy and/or chemotherapy (drugs that kill or slow the growth of cancer cells). Some subtypes of soft tissue sarcoma can also be treated with targeted therapy drugs, which are drugs that are designed to target specific changes found on certain types of cancer cells that enable them to grow and cause cancer. Chemotherapy and targeted therapy drugs may also be used after an initial treatment is complete, to help prevent the cancer from returning. The choice of treatment will depend on numerous factors related to the subtype of cancer and a person's personal situation and preferences. For further questions about treatment for soft tissue sarcoma and what your insurance covers, speak with your healthcare provider.
