Soft tissue sarcomas are cancers that occur in a variety of soft tissues within the body, especially in the arms and legs.

There are more than 50 different kinds of soft tissue sarcomas, and each one affects different groups of people across the lifespan, from children to older adults. Many soft tissue sarcomas are diagnosed in adults aged 55 and older, but children, teens, and young adults are also affected.

Soft tissue sarcomas are uncommon—fewer than 1% of all adults who have cancer are diagnosed with them. Among children, about 15% of cancer cases are soft tissue sarcomas. They are more likely to arise in people who have previously had radiation therapy for another cancer or those who have inherited genetic tumor syndromes.

As with most cancers, people with soft tissue sarcomas are more likely to have a positive outcome if they are diagnosed early, before the cancer spreads to other body parts.

“For soft tissue sarcomas confined, or localized, to one area, the treatment usually involves surgery to remove the cancer with a wide margin of normal tissue around it,” says Hari Deshpande, MD, an associate professor of medicine (medical oncology) at Yale School of Medicine. “This can be curative for some sarcomas. Sometimes, however, radiation and chemotherapy are added to the treatment plan, to help reduce the risk of the cancer coming back.”

Soft tissue sarcomas are cancers that originate in a variety of soft tissues within the body, including fat, muscle, nerves, blood vessels, and fibrous tissue. Each kind of soft tissue sarcoma may cause different symptoms and have different outcomes.

About 60% of soft tissue sarcomas are located in the arms or legs; roughly 30% are found in the trunk of the body; and the remaining 10% occur in the head or neck.

Soft tissue sarcomas may cause:

• A painless mass
• A blood clot in the leg (deep vein thrombosis)
• Swelling in the ankles or lower legs
• Abdominal pain or discomfort
• Pain, weakness, numbness, or tingling in affected body parts
• Joint pain and/or stiffness
• Fatigue
• Nausea and/or vomiting

People may be more likely to develop soft tissue sarcomas if they have, or have had:

• Radiation therapy
• Exposure to cancer-causing compounds like dioxin and polycyclic hydrocarbons
• Exposure to asbestos
• Workplace exposure to certain herbicides, including phenoxyacetic acids
• Workplace exposure to chlorophenol wood preservatives
• Chronic lymphedema
• Retinoblastoma
• A family history of certain soft tissue sarcomas
• A family history of genetic tumor syndromes, such as Li-Fraumeni syndrome and neurofibromatosis

Additionally, being HIV-positive increases the risk of one specific type of soft tissue sarcoma, Kaposi sarcoma.

Sometimes, people will make an appointment with their doctor because they’ve noticed a suspicious mass. Other times; however, doctors may discover an asymptomatic mass while providing medical care for people in an emergency setting, such as after a car accident or other injury.

If a patient visits the doctor because they have noticed a mass, the doctor will ask how long it has been present, how quickly it has grown, and whether it causes pain or discomfort.

When trying to determine the cause of the mass, a doctor will obtain a personal and family medical history. If the person has had cancer in the past, doctors will want to know if they received radiation therapy during treatment. They may also ask about a family history of cancer or certain genetic conditions that could increase the risk of soft tissue sarcomas.

During a physical examination, doctors will look for masses on the arms, legs, head, neck, or trunk. They may press on the abdomen to see if a mass is present within the abdominal cavity. Doctors may also look for skin rashes or discoloration.

Doctors may also order one or more of the following imaging studies to diagnose a soft tissue sarcoma:

• X-ray
• MRI
• CT scan
• Ultrasound
• PET scan

To confirm that a suspicious mass is a soft tissue sarcoma, doctors will biopsy the tissue. If it is cancerous, the lab analysis should reveal the type of soft tissue sarcoma present.

Different treatments are available for people with soft tissue sarcomas, including:

• Surgery. Surgery is usually the first line of treatment. When possible, doctors excise the entire mass, plus a margin of healthy tissue that is cancer-free, to ensure they have removed all of the cancer.
• Radiation therapy. After surgery, doctors may recommend radiation therapy to kill any remaining cancer cells. Radiation therapy may also be used before surgery to help shrink a tumor so that it may be more easily surgically removed.
• Chemotherapy, which can kill any cancer cells that have not been removed during surgery, may be offered by itself or in conjunction with radiation therapy. As with radiation therapy, people may receive chemotherapy before surgery to reduce the size of a tumor so that it can be removed more easily. It may also be prescribed when a soft tissue sarcoma can’t be surgically removed.
• Targeted therapy, which is designed to attack specific cancer cells without harming healthy cells. Not all types of soft tissue sarcoma may be treated this way. Targeted therapies may be used on soft tissue sarcomas that contain certain proteins, which can be targeted by specific treatments. Sometimes, doctors may offer targeted therapy to shrink tumors so that they may be surgically removed.
• Immunotherapy, which activates the body’s own immune system to fight back against cancer cells. This type of treatment is only effective against certain types of soft tissue sarcoma.
• Amputation. For cases in which a soft tissue sarcoma tumor has grown very large and has impacted the local nerves and blood vessels, doctors may need to amputate the portion of an affected limb.

The earlier that soft tissue sarcomas are diagnosed and treated, the more likely it is that an individual will respond positively to treatment. Overall, 65% of people who are diagnosed with soft tissue sarcomas survive 5 years or longer.

“At Yale, a multidisciplinary team is involved in the care of patients with soft tissue sarcomas,” says Dr. Deshpande. “This includes sarcoma surgeons, medical oncologists, radiation oncologists, nurses, and specialized radiologists and pathologists who will review the scans and biopsies to make the diagnosis and devise a treatment plan specific to each patient.”

The sarcoma tumor board meets every Friday to review cases, and patients are seen at one of Smilow Cancer Hospital’s facilities for evaluation and treatment. Many patients will receive standard treatments that can be given in most of Smilow’s facilities. Sometimes, a clinical trial will be available, especially for patients who have metastatic disease and have not had a good response to standard treatments.

Physicians at Yale are often seen as second opinions for patients with sarcoma. The subsequent care can be performed at a remote location under the guidance of a sarcoma expert if standard treatment is appropriate.