Soft tissue sarcoma, sometimes abbreviated as STS, is a rare form of cancer that begins in the soft tissues of the body. Some of the most common types of STS begin in adipose tissue, muscle tissue and the gastrointestinal tract. There are also types of STS that affect the tissues in and around the joints, connective tissue, nerve fibers and skeletal muscle. There are more than 50 subtypes of soft tissue sarcoma.
Treatment for soft tissue sarcoma depends on a number of factors. Imaging tests—such as X-rays, ultrasound, CAT scans, MRI and/or PET scans—will be used to help determine the size, location and general appearance of the tumor or tumors. These tests can also help determine if the cancer has spread to other locations in the body. Biopsies—where tissue samples from the tumor are collected for testing—are used to confirm that the tumors are STS and to determine the subtype of STS. Biopsies may be performed with a needle (called a needle biopsy), or obtained during surgery (called surgical biopsy).
Because STS is a rare condition, and because there are so many subtypes, diagnosing the specific subtype of soft tissue sarcoma can sometimes be a challenging task for healthcare providers. Some subtypes of STS, such as undifferentiated pleomorphic sarcoma (UPS), are diagnosed by exclusion—healthcare providers eliminate the other possible causes of the disease until they are left with UPS as the only reasonable explanation. It is important to work with an oncologist that specializes in soft tissue sarcoma and has experience treating the disease.
Soft tissue sarcoma may be treated with surgery, radiation therapy, chemotherapy, targeted therapy or a combination of these treatments. The type of treatment used will depend on numerous characteristics about the cancer that were learned during diagnosis, as well as characteristics about the patient, including age, overall health and medical history.
Surgery
Surgery to remove the primary tumor or tumors is the preferred option for treatment for most cases of soft tissue sarcoma. For small tumors, and cancer that has not spread to other areas of the body, surgery may be the only treatment used. For cases where the cancer has spread to other areas of the body, surgery may be used in combination with other treatments.
Radiation therapy
Radiation therapy is a treatment approach for cancer that utilizes high doses of radiation to kill cancer cells. It is also called radiotherapy. Radiation therapy may be used to shrink a tumor before surgery (to make it safer to remove surgically), or used after surgery to kill off any cancer cells that remain after a tumor was removed. In some instances, radiation is used during surgery, where it can be applied directly to the site of the cancer, a treatment approach called intraoperative radiation. Radiation is also used to shrink or kill tumors when surgery is not possible. In many instances, radiation therapy is used in combination with chemotherapy.
Chemotherapy
Chemotherapy, or chemo, is treatment with drugs that kill cancer cells, and it can be used for certain types of soft tissue sarcoma. Because chemotherapy is a systemic treatment—meaning it treats the entire body instead of a specific area of the body—it is often used when a cancer has spread beyond the initial site. With STS, chemotherapy is often used in combination with surgery, radiation and targeted therapies. Chemotherapy may also be used as an adjuvant therapy, or a therapy that is used to prevent a recurrence of cancer after surgery or other initial treatment.
Targeted therapy
Targeted therapies are drugs that are designed to target specific molecules found in cancer cells. Most work by interrupting the cellular processes that enable cancer cells to grow, spread and survive. Because they specifically target cancer cells, damage to healthy cells is kept to a minimum, though targeted therapy drugs do have side effects. Targeted therapy drugs are often used in combination with chemotherapy, and are a treatment option for only certain types of soft tissue sarcomas.
