Soft Tissue Sarcoma
Sarcomas are malignant (cancerous) tumors that develop in tissues which connect, support, or surround other structures and organs of the body. Muscles, tendons (bands of fiber that connect muscles to bones), fibrous tissues, fat, blood vessels, nerves, and synovial tissues are types of soft tissue. Soft tissue sarcomas are grouped together because they share certain microscopic characteristics, have similar symptoms, and are generally treated in similar ways. They are usually named for the type of tissue in which they begin. Examples of soft tissue sarcomas and the type of tissue in which they begin include the following:
Fibrous tissue (tissue that holds bones, muscles, and organs in place)—fibrosarcoma, malignant fibrous histiocytoma
Blood and lymph vessels—epithelioid hemangioendothelioma, angiosarcoma, lymphangiosarcoma, Kaposi sarcoma
Perivascular tissue (near or around blood vessels)—glomangiosarcoma, malignant hemangiopericytoma
Synovial tissue (tissue that lines joints, tendon sheaths, and fluid-filled sacs between tendons and bones)—synovial sarcoma
Peripheral nerves—malignant granular cell tumor, malignant peripheral nerve sheath tumor (also called malignant schwannoma or neurofibrosarcoma)
Mesenchymal cells (cells that develop into connective tissue, blood vessels, and lymphatic tissue)—gastrointestinal stromal tumor (GIST), malignant mesenchymoma
Other types of soft tissue sarcomas include alveolar soft part sarcoma, epithelioid sarcoma, desmoplastic small cell tumor, and clear cell sarcoma. At this time, scientists do not know the types of tissue in which these sarcomas begin. Many sarcomas have specific chromosomal alterations, which are used to help classify the tumors.
The doctor performs a physical exam and may use the following procedures and tests to diagnose soft tissue sarcoma:
X-rays create images of areas inside the body on film.
Computed tomography (CT), a procedure that uses special x-ray equipment to obtain cross-sectional pictures of the body, can determine whether a soft tissue tumor has metastasized (spread) to the lung or abdomen. CT scans, also called CAT scans, can also be helpful in determining the size of the tumor and whether the tumor can be accessed through surgery.
Magnetic resonance imaging (MRI) uses a powerful magnet linked to a computer to create detailed pictures of areas inside the body. MRI scans can aid in diagnosis, particularly in helping to distinguish soft tissue sarcomas from benign tumors, as well as showing the extent of the tumor. MRIs are also used to monitor the patient after treatment to see if the tumor has recurred.
A biopsy is the removal of cells or tissue for examination by a pathologist. The pathologist studies tissue samples under a microscope or performs other tests on the cells or tissue. A biopsy is the only sure way to tell whether a person has cancer.
Specialized testing of the tumor cells for chromosomal alterations may also be conducted to aid in diagnosis.
Soft tissue sarcomas can arise almost anywhere in the body. About 43 percent occur in the extremities (e.g., arms, legs); 34 percent occur in and around the internal organs (e.g., uterus, heart); 10 percent occur in the trunk (e.g., chest, back); and 13 percent occur in other locations. In very rare cases, these tumors develop in the gastrointestinal tract. A small percentage of these are GISTs. Malignant GISTs occur most commonly in the stomach and small intestine.
Soft tissue sarcomas usually appear as a lump or mass, but they rarely cause pain, swelling, or other symptoms. A lump or mass might not be a sarcoma; it could be benign (noncancerous), a different type of cancer, or another problem. It is important to see a doctor about any physical change, such as a lump or mass, because only a doctor can make a diagnosis.
Treatment for soft tissue sarcomas is determined mainly by the stage of the disease. The stage depends on the size of the tumor, the grade, and whether the cancer has spread to the lymph nodes or other parts of the body. The most important component of the stage is the tumor grade (how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread). Treatment options for soft tissue sarcomas include surgery, radiation therapy, and chemotherapy. A multidisciplinary team of cancer specialists can help plan the best treatment for patients with soft tissue sarcomas.
Surgery is the usual treatment for soft tissue sarcomas. For surgery to be effective, the surgeon must remove the entire tumor with negative margins (no cancer cells are found at the edge or border of the tissue removed during surgery). The surgeon may use special surgical techniques to minimize the amount of healthy tissue removed with the tumor. Some patients need reconstructive surgery.
Radiation therapy involves the use of high-energy x-rays to kill cancer cells. This therapy may be used before surgery to shrink the tumor, after surgery to kill any cancer cells that may remain in the body, or both before and after surgery. Radiation may come from a machine outside the body (external radiation therapy). It can also come from radioactive materials placed directly into or near the area where the cancer cells are found (internal radiation therapy or radiation implant).
Chemotherapy is the use of anticancer drugs to kill cancer cells. Chemotherapy may be used before or after surgery, and with or without radiation therapy.
The effectiveness of current anticancer drugs depends on the type of sarcoma. Some sarcomas are very responsive to chemotherapy, while others do not respond to current anticancer drugs. Some sarcomas with specific chromosomal alterations can be treated with therapies targeted to the alteration.