A soft tissue sarcoma usually produces no signs and symptoms in its early stages. As the tumor grows, it may cause:
- A noticeable lump or swelling
- Pain, if it presses on nerves or muscles
- A blockage in the stomach or intestines or gastrointestinal bleeding if the tumor is located in the abdomen or digestive tract
Soft tissue sarcomas can occur anywhere in your body, but the largest number — about 60 percent — occur in the arms, legs, hands or feet. Another 20 percent occur in the chest and abdomen. About 10 percent are found in the head and neck.
CAUSES
Generally, the cause of most soft tissue sarcomas is unknown. One of the few soft tissue sarcomas that has a known cause is Kaposi's sarcoma. It occurs in people with defective immune systems and is caused by a virus known as human herpes virus 8 (HHV8).
Additionally, in some cases, sarcomas may be hereditary, such as in:
- Basal cell nevus syndrome. In addition to an increased risk of basal cell skin cancer, people with this disorder are more likely to develop rhabdomyosarcoma or fibrosarcoma. It's caused by a genetic defect.
- Inherited retinoblastoma. This rare form of childhood eye cancer may increase a child's risk of soft tissue sarcoma and is due to inheritance of a mutated retinoblastoma gene.
- Li-Fraumeni syndrome. This condition is characterized by an increased risk of many malignancies, including sarcomas, breast cancer, brain cancer and others. People with this syndrome appear to be particularly susceptible to the side effects of radiation therapy.
- Gardner syndrome. This hereditary disease leads to precancerous and cancerous growths in the intestines and abdomen.
- Neurofibromatosis. This condition results in developmental changes in the nervous system, causing nerve sheath tumors. About 1 in 20 people with neurofibromatosis develops malignant tumors.
- Tuberous sclerosis. Benign tumors, seizures and learning problems are common with this disease, as is an increased risk of rhabdomyosarcoma.
- Werner syndrome. A defect in the gene RECQL2 causes numerous health problems, including an increased risk of soft tissue sarcomas.
Radiation exposure
Radiation is occasionally associated with sarcomas. These have usually occurred as a side effect of radiation therapy given for other cancers, such as breast cancer or lymphoma. But radiation therapy is becoming more and more sophisticated, which may lead to fewer such side effects. For example, doctors today are better able to regulate doses of radiation and precisely target the tumor being treated.
Chemical exposure
Another factor that may increase your risk of soft tissue sarcoma is exposure to high doses of chemicals such as:
- Vinyl chloride, used in making plastics
- Dioxin, an unwanted byproduct of incineration
- Herbicides that contain the chemical phenoxyacetic acid
If it's suspected that you have sarcoma, your doctor will take a medical history, perform a physical exam and may also remove a sample of tissue (biopsy) from the tumor for examination. Techniques for biopsy of a suspected soft tissue sarcoma include:
- Needle biopsy. Your doctor uses a thin needle to remove small pieces of tissue from the tumor. There are two types of needle biopsy — fine-needle aspiration and core biopsy. A core biopsy involves using a slightly larger needle to remove a small, solid core of tissue.
- Surgical biopsy. Your doctor makes an incision through your skin and removes either the entire tumor (excisional biopsy) or a portion of the tumor (incisional biopsy). In some cases you may need only local anesthesia. For a larger or deep-seated tumor, you'll likely require general anesthesia for the procedure. It's important that a doctor experienced in the treatment of sarcomas perform the excisional biopsy.
Imaging tests, such as X-rays, computerized tomography (CT) scans, ultrasound, magnetic resonance imaging (MRI) and positron emission tomography (PET), also may be done to enable your doctor to see and evaluate the area of concern.
Grading and staging
Besides determining whether it is malignant, examining tissue can determine how aggressive the cancer is (its grade). Further testing, such as with imaging scans and blood tests, can help determine if the cancer has spread and, if so, how far (its stage).
- Stage I. These tumors are generally small, but what's important is that the tissue cells appear normal. Additionally, the sarcoma hasn't spread to the lymph nodes or to distant sites.
- Stage II. In more advanced soft tissue sarcomas, the cells begin to look abnormal and they may be dividing rapidly. At this stage, however, it still hasn't spread to the lymph nodes or other areas of the body.
- Stage III. Not only do the cells look abnormal and divide rapidly, malignant cells are found in one or more lymph nodes.
- Stage IV. At this stage, the cells are abnormal and rapidly dividing, and the cancer can be found in the lymph nodes and in other parts of the body.
As with other cancers, treatment for sarcomas depends on the size, type, location and stage of the sarcoma, including whether it has spread to the lymph nodes or other parts of your body, and your overall health.
Surgery
Surgery is the most common treatment for soft tissue sarcomas, especially if malignant cells haven't spread to other parts of the body. Surgery generally involves removing the cancer and some healthy tissue surrounding it. If the sarcoma has spread, surgical removal of the primary and secondary tumors may be possible.
Previously, amputation was a common treatment for soft tissue sarcomas in an arm or leg. Today, advances in surgical techniques and chemotherapy before surgery (neoadjuvant chemotherapy) or after surgery (adjuvant chemotherapy) and radiation therapy make limb-sparing surgery possible in most cases. However, amputation may be necessary to remove all of the malignant cells from soft tissue sarcoma in an arm or leg that has invaded nerves, arteries or muscles.
Radiation therapy
Radiation therapy — also called radiotherapy or X-ray therapy — involves treating cancer with beams of high-energy particles, or waves (radiation), such as gamma rays or X-rays. Although radiation can affect healthy cells as well as cancer cells, it's much more harmful to cancer cells. In addition, normal cells can recover from the effects of radiation more easily than cancer cells can.
Radiation therapy may be recommended to treat your soft tissue sarcoma. Your doctor may suggest using radiation therapy before surgery to shrink a cancerous tumor or after surgery to stop the growth of any remaining cancer cells. You may also receive chemotherapy at the same time as radiation in an effort to make the radiation more effective.
Chemotherapy
Chemotherapy uses medications to kill rapidly dividing cells. These cells include cancer cells, which continuously divide to form more cells, and healthy cells that divide quickly, such as those in your bone marrow, gastrointestinal tract, reproductive system and hair follicles. Unlike radiation therapy, which treats only the part of your body exposed to the radiation, chemotherapy treats your body as a whole (systemically). As a result, it treats cells that may have spread beyond where the cancer originated.
The role of chemotherapy in the treatment of soft tissue sarcoma isn't clear, because not all studies have had positive results. However, chemotherapy has been found effective in treating rhabdomyosarcomas.
In addition to chemotherapy, some drugs inhibit certain enzymes that are critical to the development and growth of a tumor. One of these drugs, imatinib (Gleevec), is used to treat a type of sarcoma called gastrointestinal stromal tumor. Other types of cancer-fighting drugs and new combinations of treatments are being explored in clinical trials.
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