This information explains soft tissue sarcoma, including risk factors, symptoms, and treatment.

Soft tissue sarcoma is a rare, malignant tumor that develops in the connective tissues. Connective tissues include muscle, fat, tendon, and cartilage.

Soft tissue sarcomas are rare, making up less than 1% of all cancers. Every year, about 14,000 people are diagnosed with this cancer. Sarcomas can occur at any age and are equally common in both men and women. 

Risk Factors

We do not know exactly what causes soft tissue sarcoma. However, some risk factors include:

  • Having had previous radiation therapy
  • Genetic conditions such as:
    • Neurofibromatosis
    • Gardner's syndrome
    • Li-Fraumeni syndrome
    • Retinoblastoma
  • Being exposed to cancer-causing agents such as:
    • Insecticides or herbicides
    • Vinyl chlorides
  • Having chronic lymphedema.  Lymphedema develops when your arms, hands, legs, or feet swell with lymphatic fluid. 

Types of Soft Tissue Sarcomas

Soft tissue sarcomas are grouped by what they look like under the microscope and their gene abnormalities. The most common types of sarcomas are:

  • Liposarcomas, which look similar to fat tissues
  • Leiomyosarcomas, which look similar to smooth, involuntary muscles found in the:
    • Uterus
    • Wall of the digestive tract
    • Walls of blood vessels
  • Rhabdomyosarcomas, which look similar to skeletal muscles. They are usually seen in children, though they can rarely develop in adults.
  • Malignant fibrous histiocytomas (MFH) and undifferentiated pleomorphic sarcoma, which do not look like any normal tissues
  • Synovial sarcomas, which do not look like normal tissues. They can develop anywhere in the body and are most common in adolescents and young adults

Common Sites for Soft Tissue Sarcomas

Soft tissue sarcomas can develop almost anywhere in the body. About half develop in the limbs, usually in the thigh. Others can arise in the pelvis, trunk, or retroperitoneum, which is the space in your abdomen behind your abdominal lining.

Signs and Symptoms

The signs and symptoms of soft tissue sarcomas depend on where the tumor is found.

Soft tissue sarcomas that are found in a limb usually appear as a painless lump. Some symptoms of soft tissue sarcomas include:

Some patients may first notice the lump after an injury to the area and think that the injury is the cause of the tumor. However, doctors think that it just draws attention to a tumor that was already there.

Diagnosis

Your doctor will determine if a biopsy (sample of tissue) of the tumor is needed. Depending on the location of the tumor, he or she will order a computed tomography (CT) scan or magnetic resonance imaging (MRI) to see how big it is and how close it is to blood vessels, muscles, or other organs.

If you need a biopsy, it can be done in your doctor’s office or in Interventional Radiology. The tissue sample will be sent to a pathologist who will examine it under a microscope.

Unlike other cancers, sarcomas do not have a staging system. Low-grade sarcomas have a low risk (less than 5%) of metastasizing (spreading to other areas of the body). High-grade sarcomas have a higher risk of metastasizing, most commonly to the lungs. Sarcomas usually do not spread to the lymph nodes.

Treatment

Your surgeon, medical oncologist, and radiation oncologist will work together to plan the best treatment for you. They will meet with you and discuss your treatment options. They will look at the cell type, grade and location of the tumor before recommending the best treatment for you. 

Surgery

Surgery is the main treatment for soft tissue sarcoma. The goal of surgery is to take out the tumor with a margin of healthy tissue to make sure that all the cancer was removed. Your doctor or nurse will explain the details of your specific surgery. Your nurse will help you prepare and will give you a resource called Getting Ready for Surgery.  

Radiation Therapy

Radiation therapy uses high-energy x-rays to kill cancer cells. It can be used alone or be added to your treatment before or after your surgery. 

During radiation therapy, a beam of radiation is directed to the tumor site from a treatment machine. The beam passes through the body and destroys cancer cells in its path. If radiation therapy is part of your treatment, you will get radiation every weekday for several weeks. Your doctor or nurse will discuss the side effects of radiation with you and how to care for yourself during treatment.

Chemotherapy

Chemotherapy is treatment with medications that destroy cancer cells anywhere in the body. You can get chemotherapy either through a vein (intravenously) or by mouth via a pill (orally). You can get chemotherapy before your  surgery to reduce the size of a large tumor and make it easier to remove. You can also get chemotherapy after your surgery.

Chemotherapy can consist of one medication or several medications. You can get chemotherapy in an outpatient or inpatient setting. Your doctor and nurse will discuss your treatment plan with you. They will also explain the possible side effects. You will receive more information about your chemotherapy regimen, as well as the National Cancer Institute booklet, Chemotherapy and You.

Long-Term Care

Your care at Memorial Sloan Kettering Cancer Center (MSK) will be a long-term process. You will see your doctor every 4 to 6 months for the first 3 years after you finish your treatment. In these follow up visits, you will have a physical exam and a chest x-ray or a CT scan.

After the early follow-up period, you will see your doctor every 6 or 12 months for the next 5 years. After that, you will see your doctor only once a year or once every 2 years.

Your long-term care is important to your doctors and nurses. Please contact them at any point during your care if you have any questions or concerns.

Resources

The Kristen Ann Carr Fund is a great resource for patients with soft tissue sarcoma. They produce a newsletter called Sarcoma Update once a year. For more information about soft tissue sarcoma and the newsletter, go to: www.sarcoma.com.