Ewing sarcoma is a cancer that occurs primarily in the bone or soft tissue. Ewing sarcoma can occur in any bone, but most often it is found in the long bones such as the femur (thigh), tibia (shin), or humerus (upper arm). It can involve the muscle and the soft tissues around the tumor site as well. Ewing sarcoma cells can also spread (metastasize) to other areas of the body including the bone marrow, lungs, kidneys, heart, adrenal gland, and other soft tissues.
Ewing sarcoma accounts for about 2 percent to 3 percent of childhood cancers. About 250 children and adolescents will be diagnosed with Ewing sarcoma in the US in 2008. It is the second most common malignant bone tumor in children and adolescents. Ewing sarcoma most often occurs in children between the ages of ten and 20. More males are affected than females.
The exact cause of Ewing sarcoma is not fully understood. There seems to be no known risk factors or prevention measures available. However, researchers have discovered chromosomal changes in a cell's DNA that can lead to Ewing sarcoma formation. These changes are not inherited. They develop in children after they are born for no apparent reason.
In nearly 85 percent of these cases, the change involved the fusing of genetic material between chromosomes #11 and #22. When a certain piece of chromosome #11 is placed next to the EWS gene on chromosome #22, the EWS gene gets "switched on." This activation leads to an overgrowth of the cells and eventually the development of cancer. The exact mechanism remains unclear, but this important discovery has led to improvements in diagnosing Ewing sarcoma.
Some physicians classify Ewing sarcoma as a primitive neuroectodermal tumor (PNET). This means the tumor may have started in fetal, or embryonic, tissue that has developed into nerve tissue.
The following are the most common symptoms of Ewing sarcoma. However, each child may experience symptoms differently. Symptoms may include, but are not limited, to the following:
- pain around the site of the tumor
- swelling and/or redness around the site of the tumor
- weight loss, decreased appetite
- paralysis and/or incontinence (if the tumor is in the spinal region)
- symptoms related to nerve compression from tumor (e.g., numbness, tingling, paralysis, etc.)
The symptoms of Ewing sarcoma may resemble other conditions or medical problems. Always consult your child's physician for a diagnosis.
In addition to a complete medical history and physical examination of your child, diagnostic procedures for Ewing sarcoma may include:
- multiple imaging studies, such as:
- x-rays - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
- bone scans - a nuclear imaging method to evaluate any degenerative and/or arthritic changes in the joints; to detect bone diseases and tumors; to determine the cause of bone pain or inflammation. This test is to rule out any infection or fractures.
- 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 is done to rule out any associated abnormalities of the spinal cord and nerves.
- computed tomography scan (Also called a 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 than general x-rays.
- positron emission tomography (PET) scan - radioactive-tagged glucose (sugar) is injected into the bloodstream. Tissues that use the glucose more than normal tissues (such as tumors) can be detected by a scanning machine. PET scans can be used to find small tumors or to check if treatment for a known tumor is working.
- blood tests (including blood chemistries)
- biopsy of the tumor - a procedure in which tissue samples are removed (with a needle or during surgery) from the body for examination under a microscope; to determine if cancer or other abnormal cells are present; to remove tissue from the affected bone.
- bone marrow aspiration and/or biopsy - a procedure that involves taking a small amount of bone marrow fluid (aspiration) and/or solid bone marrow tissue (called a core biopsy), usually from the hip bones, to be examined for the number, size, and maturity of blood cells and/or abnormal cells.
Ewing sarcoma is difficult to distinguish from other similar tumors. Diagnosis is often made by excluding all other common solid tumors, and by the use of genetic studies.
Specific treatment for Ewing sarcoma will be determined by your child's physician based on:
- your child's age, overall health, and medical history
- extent of the disease
- your child's tolerance of specific medications, procedures, or therapies
- expectations for the course of the disease
- your opinion or preference
Treatment may include one, or more, of the following:
- radiation therapy
- resections for metastases (e.g., pulmonary resections of cancer cells in the lung)
- rehabilitation including physical and occupational therapy, and psychosocial adaptation
- prosthesis fitting and training
- supportive care (for the side effects of treatment)
- antibiotics (to prevent and treat infections)
- continual follow-up care (to determine response to treatment, detect recurrent disease, and manage late effects of treatment)
Prognosis for Ewing sarcoma greatly depends on:
- the extent of the disease.
- the size and location of the tumor.
- presence or 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.
A person who was treated for Ewing sarcoma as a child or adolescent may develop effects months or years after treatment ends. These effects are called late effects. The kind of late effects one develops depends on the location of the tumor and the way it was treated.
Some types of treatment may later affect fertility. If this side effect is permanent, it will cause infertility, or the inability to have children. Both men and women can be affected.
As with any cancer, prognosis and long-term survival can vary greatly from child to child. Every child is unique and treatment and prognosis is structured around the child's needs. Prompt medical attention and aggressive therapy are important for the best prognosis. Continuous follow-up care is essential for a child diagnosed with Ewing sarcoma. Late effects of radiation and chemotherapy, as well as second malignancies, can occur in survivors of Ewing sarcoma. New methods are continually being discovered to improve treatment and to decrease side effects.
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