Gastrointestinal stromal tumor (GIST) is a type of soft tissue sarcoma, a cancer that occurs in the wall of the stomach, intestines, or rectum. The cells of each type of sarcoma look different under a microscope, based on the type of soft tissue in which the cancer began.
Soft tissue sarcoma is a disease in which malignant (cancer) cells form in the soft tissues of the body. The soft tissues of the body include the muscles, tendons (bands of fiber that connect muscles to bones), fat, blood vessels, lymph vessels, nerves, and tissues around joints. Adult soft tissue sarcomas can form almost anywhere in the body, but are most common in the legs, abdomen, arms, and trunk.
Having certain inherited disorders can increase the risk of developing adult soft tissue sarcoma.
Anything that increases your risk of getting a disease is called a risk factor. Risk factors for soft tissue sarcoma include the following inherited disorders:
- Neurofibromatosis type 1 (von Recklinghausen disease or NF1).
- Tuberous sclerosis.
- Familial adenomatous polyposis (FAP).
- Li-Fraumeni syndrome.
- Werner syndrome.
- Basal cell nevus syndrome.
Other risk factors for soft tissue sarcoma include past treatment with radiation therapy during childhood or for the following types of cancer:
- Breast cancer.
- Cervical cancer.
Possible signs of adult soft tissue sarcoma include a lump or swelling in soft tissue of the body.
A sarcoma may appear as a painless lump under the skin, often on an arm or a leg. Sarcomas that begin in the abdomen may not cause symptoms until they become very large. As the sarcoma grows larger and presses on nearby organs, nerves, muscles, or blood vessels, symptoms may include:
- Trouble breathing.
Other conditions may cause the same symptoms that soft tissue sarcomas do. A doctor should be consulted if any of these problems occur.
Adult soft tissue sarcoma is diagnosed with a biopsy.
If a soft tissue sarcoma is suspected, a biopsy will be done. The type of biopsy that is done will be based on the size and location of the tumor. There are two types of biopsy that may be used:
- Incisional biopsy: The removal of part of a lump or a sample of tissue.
- Core biopsy: The removal of tissue using a wide needle.
Samples will be taken from the primary tumor, lymph nodes, and other suspicious areas. A pathologist views the tissue under a microscope to look for cancer cells and to find out the grade of the tumor. The grade of a tumor depends on how abnormal the cancer cells look under a microscope and how quickly the cells are dividing. High-grade tumors usually grow and spread more quickly than low-grade tumors. Because soft tissue sarcoma can be hard to diagnose, patients should ask to have biopsy samples checked by a pathologist who has experience in diagnosing soft tissue sarcoma.
Certain factors affect treatment options and prognosis (chance of recovery).
The treatment options and prognosis (chance of recovery) depend on the following:
- The type of soft tissue sarcoma.
- The size, grade, and stage of the tumor.
- Where the tumor is in the body.
- Whether the entire tumor is removed by surgery.
- The patient's age and general health.
- Whether the cancer has recurred (come back).
Recurrent Adult Soft Tissue Sarcoma
Recurrent adult soft tissue sarcoma is cancer that has recurred (come back) after it has been treated. The cancer may come back in the same soft tissue or in other parts of the body.
Staging the Disease
After adult soft tissue sarcoma has been diagnosed, tests are done to find out if cancer cells have spread within the soft tissue or to other parts of the body. The process used to find out if cancer has spread within the soft tissue or to other parts of the body is called staging. Staging of soft tissue sarcoma is also based on the grade and size of the tumor, whether it is superficial (close to the skin's surface) or deep, and whether it has spread to the lymph nodes or other parts of the body. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment.
The following tests and procedures may be used in the staging process:
- Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.
- X-rays: An x-ray is a type of energy beam that can go through the body onto film, making pictures of areas inside the body.
- Laboratory tests: Medical procedures that test samples of tissue, blood, urine, or other substances in the body. These tests help to diagnose disease, plan and check treatment, or monitor the disease over time.
- CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside of the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
- MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
The results of these tests are viewed together with the results of the tumor biopsies to determine the stage of the soft tissue sarcoma.
The following stages are used for adult soft tissue sarcoma:
In stage I, the tumor is any size, low-grade (likely to grow and spread slowly), and may be either superficial (close to the skin's surface) or deep.
|Pea, peanut, walnut, and lime show tumor sizes.
Image courtesy of http://teresewinslow.com
In stage II, the tumor is high-grade (likely to grow and spread quickly) and either:
- 5 centimeters or smaller and can be superficial (close to the skin's surface) or deep; or
- larger than 5 centimeters and superficial.
In stage III, the tumor is high-grade, larger than 5 centimeters, and deep.
In stage IV, the tumor is any size, any grade, and has spread to nearby lymph nodes or to other parts of the body.
Different types of treatments are available for patients with adult soft tissue sarcoma. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. Before starting treatment, patients may want to think about taking part in a clinical trial. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment..
Surgery is the most common treatment for adult soft tissue sarcoma. For some soft-tissue sarcomas, removal of the tumor in surgery may be the only treatment needed. The following surgical procedures may be used:
- Mohs microsurgery: A procedure in which the tumor is cut from the skin in thin layers. During surgery, the edges of the tumor and each layer of tumor removed are viewed through a microscope to check for cancer cells. Layers continue to be removed until no more cancer cells are seen. This type of surgery removes as little normal tissue as possible and is often used where appearance is important, such as on the skin.
- Wide local excision: Removal of the tumor along with some normal tissue around it.
- Limb-sparing surgery: Removal of the tumor in an arm or leg without amputation, so the use and appearance of the limb is saved. Radiation therapy or chemotherapy may be given first to shrink the tumor. The tumor is then removed in a wide local excision. Tissue and bone that are removed may be replaced with a graft using tissue and bone taken from another part of the patient's body, or with an implant such as artificial bone.
- Amputation: Surgery to remove part or all of a limb or appendage, such as an arm or leg.
- Lymphadenectomy: Removal of the lymph nodes that contain cancer.
Radiation therapy or chemotherapy may be given before or after surgery to remove the tumor. When given before surgery, radiation therapy or chemotherapy will make the tumor smaller and reduce the amount of tissue that needs to be removed during surgery. Treatment given before surgery is called neoadjuvant therapy. When given after surgery, radiation therapy or chemotherapy will kill any remaining cancer cells. Treatment given after the surgery is called adjuvant therapy.
Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. The way the radiation therapy is given depends on the type and stage of the cancer being treated.
Fast neutron radiation therapy is a type of high-energy external radiation therapy. A radiation therapy machine aims tiny, invisible particles, called neutrons, at the cancer cells to kill them. Fast neutron radiation therapy uses a higher-energy radiation than the x-ray type of radiation therapy. This allows the same amount of radiation to be given in fewer treatments.
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body ( systemic chemotherapy). When chemotherapy is placed directly into the spinal column, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas ( regional chemotherapy). The way the chemotherapy is given depends on the type and stage of the cancer being treated.
High-dose chemotherapy with stem cell transplant
High-dose chemotherapy with stem cell transplant is a method of giving high doses of chemotherapy and replacing blood -forming cells destroyed by the cancer treatment. Stem cells (immature blood cells) are removed from the blood or bone marrow of the patient or a donor and are frozen and stored. After the chemotherapy is completed, the stored stem cells are thawed and given back to the patient through an infusion. These reinfused stem cells grow into (and restore) the body's blood cells.
Targeted drug therapy
Targeted therapy is a type of treatment that uses drugs or other substances to find and attack specific cancer cells without harming normal cells. Imatinib (Gleevec) is a new type of targeted therapy called a tyrosine kinase inhibitor. It finds and blocks an abnormal protein on cancer cells that causes them to divide and grow. Targeted therapy may be used for gastrointestinal stromal tumors that cannot be removed by surgery or that have spread to other parts of the body.
Treatment Options by Stage
Stage I Adult Soft Tissue Sarcoma
Treatment of stage I adult soft tissue sarcoma may include the following1:
- Surgery ( wide local excision or Mohs microsurgery).
- Radiation therapy before and/or after surgery.
If cancer is found in the head, neck, abdomen, or chest, treatment may include the following:
- Radiation therapy before or after surgery.
- Fast neutron radiation therapy.
Check for clinical trials from NCI's PDQ Cancer Clinical Trials Registry that are now accepting patients with stage I adult soft tissue sarcoma.
Stage II and III Adult Soft Tissue Sarcoma
Treatment of stage II and III adult soft tissue sarcoma may include the following:
- Surgery ( wide local excision).
- Surgery (wide local excision) with radiation therapy, for large tumors.
- High-dose radiation therapy for tumors that cannot be removed by surgery.
- Radiation therapy or chemotherapy before limb-sparing surgery. Radiation therapy may also be given after surgery.
- A clinical trial of surgery followed by chemotherapy, for large tumors.
Check for clinical trials from NCI's PDQ Cancer Clinical Trials Registry that are now accepting patients with stage II adult soft tissue sarcoma and stage III adult soft tissue sarcoma.
Stage IV Adult Soft Tissue Sarcoma
Treatment of stage IV adult soft tissue sarcoma that involves lymph nodes may include the following:
- Surgery ( wide local excision) with or without lymphadenectomy. Radiation therapy may also be given after surgery.
- Radiation therapy before and after surgery.
- A clinical trial of surgery followed by chemotherapy.
- A clinical trial of targeted drug therapy (Gleevec) for gastrointestinal stromal tumors.
Treatment of stage IV adult soft tissue sarcoma that involves internal organs of the body may include the following:
- Surgery (wide local excision).
- Surgery to remove as much of the tumor as possible, followed by radiation therapy.
- High-dose radiation therapy, with or without chemotherapy, for tumors that cannot be removed by surgery.
- Chemotherapy with 1 or more anticancer drugs, before surgery or as palliative therapy to relieve symptoms and improve the quality of life.
- A clinical trial of chemotherapy with or without stem cell transplant.
- A clinical trial of chemotherapy following surgery to remove cancer that has spread to the lungs.
- A clinical trial of targeted drug therapy (Gleevec) for gastrointestinal stromal tumors.
These treatments may be followed by surgery to remove lesions on the lungs.
Recurrent Soft Tissue Sarcoma
Treatment Options for Recurrent Adult Soft Tissue Sarcoma
Treatment of recurrent adult soft tissue sarcoma may include the following:
- Surgery ( wide local excision) with radiation therapy before or after surgery.
- Surgery ( amputation).
- Radiation therapy followed by limb-sparing surgery.
- Surgery to remove cancer that has recurred in the lungs.
- Chemotherapy with 1 or more anticancer drugs.
- A clinical trial of new anticancer drugs.
- A clinical trial of high-dose chemotherapy with or without stem cell transplant.