 Leiomyosarcoma
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Leiomyosarcoma is a very rare cancer that arises from muscle tissue. It can occur in muscle virtually anywhere in the body, although it tends to develop in muscle tissue of the gastrointestinal tract, uterus and retroperitoneal region. The retroperitoneum is the space between the membrane that lines the abdominal cavity, called the peritoneum, and the posterior abdominal wall. This region contains the kidneys, pancreas, and part of the aorta and inferior vena cava. In children, leiomyosarcoma is the most common type of tumor found in the retroperitoneum.
Leiomyosarcoma can spread (metastasize) to other areas of the body. It is a very rare tumor and is considered a soft tissue sarcoma, cancer that originates in soft connective tissues of the body which includes fat, muscles, tendons, nerves, synovial tissue, blood vessels and other fibrous tissue. As a group, soft tissue sarcomas, outside of rhabdomysarcoma which is slightly more common, account for less than 1 percent of all new cancer cases each year and 3 percent of all childhood tumors. Leiomyosarcoma accounts for 7 to 11 percent of all soft tissue sarcomas among adults and children.
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The exact cause of leiomyosarcoma is not entirely understood, however, studies have indicated that genetic alterations may play a role in the formation of all soft tissue sarcomas. Researchers have studied a small number of families that contain several members of one generation who have developed soft tissue sarcomas. In addition, limited studies have shown a possible link between soft tissue sarcomas and the development of other types of cancer.
Certain inherited diseases are also associated with an increased risk of developing soft tissue sarcomas. There seems to be an association between leiomyosarcoma and Epstein-Barr virus infection. Those with acquired immunodeficiency syndrome (AIDS) and those who are undergoing immunosupression therapy for renal transplantation are at increased risk for developing leiomyosarcoma.
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Because soft tissue sarcomas affect tissue that is elastic and easily moved, a tumor may exist for a long time before being discovered, growing large and pushing aside surrounding tissue. The following are the most common symptoms of leiomyosarcoma. However, each child may experience symptoms differently. The symptoms of this disease vary greatly with the size, location and spread of the tumor. Symptoms may include:
- A painless swelling or mass anywhere on the body
- Pain or soreness caused by compressed nerves or muscles
- Limping or other difficulty using the legs, feet, arms or hands.
The symptoms of leiomyosarcoma may resemble other conditions or medical problems. Always consult your child's physician for a diagnosis.
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In addition to a complete medical history and physical examination, the most conclusive diagnostic procedure for leiomyosarcoma is a biopsy, a single tissue sample taken from the tumor through a simple surgical procedure. The tumor's cellular appearance under a microscope establishes a diagnosis and enables doctors to distinguish it from other types of cancer.
Your child will likely undergo various imaging studies that will include one or more of the following:
- x-rays - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film. X-rays are very useful in the diagnosis of soft tissue tumors and frequently allow the physician to distinguish between benign and malignant tumors. It is often the first diagnostic study performed and it usually gives the doctor information regarding the need for further testing.
- Magnetic Resonance Imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies and a computer to produce detailed images of organs and structures within the body. This test outlines the extent of the tumor and its relationship to surrounding muscles, nerves and blood vessels.
- Computerized Tomography scan (also called CT or CAT scan) - a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices)both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat and organs. CT scans are more detailed that general x-rays. They are used primarily to assess the chest and lung for matastatic tumors.
- Bone scans - a nuclear imaging method used to evaluate any bone that is involved with the tumor. It is use to detect bone and metastatic tumors and may be used to determine if there are abnormalities in other bones.
Other tests include:
- Complete blood count (CBC) - a measurement of size, number and maturity of different blood cells in a specific volume of blood
- Blood tests - (including blood chemistries)
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Once leiomyosarcoma has been diagnosed, the tumor is staged. This process indicates how far the tumor has spread from its original location. The stage of a tumor suggests which form of treatment is most appropriate, and predicts how the condition will probably respond to therapy.
A leiomyosarcoma may be localized, meaning it has not spread beyond the muscle tissue where it arose or beyond nearby tissues, or metastatic, meaning it has spread to lungs, bones or to other organs or structures of the body.
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Specific treatment for leiomyosarcoma will be determined by your child's physician based on:
- Your child's age, overall health, and medical history
- Extent of the disease
- The presence or absence of metastasis
- Your child's tolerance for specific medications, procedures or therapies
- How your child's doctor expects the disease may progress
- Your opionion and preference
Treatment may include some combination of the following:
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Surgery includes biopsy and wide surgical removal of the entire tumor, along with surrounding healthy muscle and other tissue. If the tumor is located in a limb, it may be necessary to remove all or part of the limb. In most cases limb-sparing surgery is used to avoid amputation.
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- Limb-salvage surgery: Limb-salvage surgery is indicated only if your child's orthopaedic surgeon determines that it is possible that the tumor, and wide margins of healthy tissue surrounding the tumor, can be removed. Through limb-salvage surgery, all of the tissue involved with the tumor, including some degree of muscle surrounding it and nearby lymph nodes, are removed, unaffected tendons, nerves and vessels are saved. If bone is also removed, it is usually replaced with a bone graft or with a metal rod. Subsequent surgery may be needed to repair or replace rods, which can become loose or break. Patients who have undergone limb-salvage surgery need intensive rehabilitation. It may take as long as a year for a patient to regain full use of a leg following limb-salvage surgery. Some patients who undergo limb salvage proceduresmay eventually have to have the limb amputated
- Amputation: In certain cases, if your child's orthopaedic surgeon determines that the tumor cannot be removed because, for example, it involves the nerves and blood vessels, amputation may be the only option. During the operation, doctors ensure that muscles and skin form a cuff around the amputated bone. A cast is applied in the operating room which permits a temporary artificial leg (prosthesis) to be applied during the first few post-operative days for walking. Crutches are used for several weeks. As the swelling decreases (10 to 14 days) the patient is fitted for a plastic, temporary socket and prosthesis, which is used for 3 to 4 months until the stump is healed sufficiently to accept a permanent artificial leg. The advantages of an amputation are that it is a simple operation with minimal chances of surgical complication and it definitively removes the local tumor. The functional outcome is good with the modern prostheses available today and with with "immediate-fit" prostheses applied in the operating room. Although the patient will probably have a limp with above-the-knee amputations, the procedure is functional and stable. He/she will be able to walk, climb stairs, swim (with the prosthesis on or off) and participate in many sports such as skiing, basketball, baseball, and tennis although running will be limited. The functional limitations are left to the imagination and determination of the patient.
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Radiation and chemotherapy may also be used to treat some forms of leiomyosarcoma. However, these therapies have proven to be ineffective against certain types of leiomyosarcoma, such as the type that arises from the gastrointestinal tract. If these treatments are used, either or both are given before surgery to shrink the tumor, or after surgery to kill remaining cancer cells. The following is a description of both therapies:
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- Radiation therapy - using high energy rays (radiation) from a specialized machine to damage or kill cancer cells and shrink tumors. This is sometimes used in conjunction with surgery for leiomyosarcoma, either before or after resection of the tumor. Only on rare occasions is radiation alone used for the treatment of a primary tumor.
- Chemotherapy - a drug treatment that works by interfering with the cancer cell's ability to grow or reproduce. Different groups of drugs work in different ways to fight cancer cells and shrink tumors. Chemotherapy may be used alone for some types of cancer or in conjunction with other therapy such as radiation or surgery. Often, a combination of chemotherapy drugs is used to fight a specific cancer. Certain chemotherapy drugs may be given in a specific order depending on the type of cancer it is being used to treat. While chemotherapy can be quite effective in treating certain cancers, the agents do not differentiate normal healthy cells from cancer cells. Because of this, there can be many adverse side effects during treatment. Being able to anticipate these side effects can help the care team, parents, and child prepare and, in some cases, prevent these symtpoms from occurring, if possible. Chemotherapy is a systemic treatment, meaning it is introduced into the bloodstream and travels throughout the body to kill cancer cells. Chemotherapy may be given:
- As an injection into the muscle or fat tissue
- Intravenously (directly to the bloodstream; also called IV)
- Intrathecally (given directly into the spinal column with a needle)
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Supportive care refers to any type of treatment to prevent and treat infections, side effects of treatments and complications and to keep your child comfortable during treatment.
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A schedule of follow-up care is determined by your child's physician and other members of you care team to monitor ongoing response to treatment and possible late effects of treatment.
Treatment options will vary greatly, depending on your child's individual situation. Your child's physician and other members of your care team will discuss these with you in-depth.
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Prognosis greatly depends on:
- The extent of the disease
- The size and location of the tumor
- A presence of absence of metastasis
- The tumor's response to therapy
- The age and overall health of your child
- Your child's tolerance of specific medications, procedures, or therapies
- New developments in treatment
As with any cancer, prognosis and long-term survival can vary greatly from individual to individual. Prompt medical attention and aggressive therapy are important for the best prognosis. Continuous follow-up care is essential for a child diagnosed with leiomyosarcoma. Side effects of radiation and chemotherapy, as well as recurrence of the disease, can occur in survivors of this condition.
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Children's Hospital and Dana-Farber Cancer Institute are conducting numerous research studies that will help clinicians better understand and treat soft tissue sarcomas.
Other types of treatment currently being studied include:
- Angiogenesis inhibitors - substances that may be able to prevent the growth of tumors by blocking the formation of new blood vessels that feed the tumors.
- Biological therapies - a wide range of substances that may be able to involve the body's own immune system to fight cancer or lessen harmful side effects of some treatments.
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