What is Ewing sarcoma?
Ewing sarcoma is a cancer that occurs primarily in the bone or soft tissue. Ewing sarcoma can occur in any bone, but is most often found in the extremities and can involve muscle and the soft tissues around the tumor site. 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 to 3 percent of childhood cancers. About 250 children and adolescents are diagnosed with Ewing sarcoma each year in the US. 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. The number of males affected is slightly higher than the number of females.
What causes Ewing sarcoma?
The majority of Ewing sarcomas result from a chromosome rearrangement between chromosomes #11 and #22. This rearrangement changes the position and function of genes, causing a fusion of genes referred to as a "fusion transcript." Over 90 percent of individuals have an abnormal fusion transcript, involving two genes known as EWS and FLI1. This important discovery has led to improvements in diagnosing Ewing sarcoma.
Similar to osteogenic sarcoma, trauma or injury is sometimes involved with the site at the time of diagnosis. However, this trauma is thought to bring the condition to attention rather than to have any causal relationship.
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.
What are the symptoms of Ewing sarcoma?
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.
How is Ewing sarcoma diagnosed?
Children’s Hospital of Orange County is a leader in diagnosing and treating childhood bone cancer. The CHOC Cancer Institute takes an advanced approach to this condition, offering patients access to the latest treatment alternatives in a compassionate, patient-centered environment.
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.
- 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.
Stages of Ewing’s Sarcoma:
Once Ewing’s sarcoma is found, more tests will be done to determine if the cancer cells have spread to others parts of the body. This is called staging. Currently, there is no formal staging system for the Ewing’s family of tumors. Instead, most patients are grouped depending on whether cancer is found in only one part of the body (localized disease) or whether cancer has spread from one part of the body to another (metastatic disease). Treatment is tailored to where the cancer is located and how far the disease has spread.
The following groups are used for the Ewing’s family of tumors:
- Localized– The cancer cells have not been shown to have spread beyond the bone in which the cancer began or are found only in the bone and nearby tissues.
- Metastatic– The cancer cells have spread from the bone in which the cancer began to other parts of the body. The cancer most often spreads to the lungs, other bones, and bone marrow (the spongy tissue inside of the large bones of the body that makes red blood cells). Spread of cancer to the lymph nodes (small bean-shaped structures found throughout the body which produce and store infection-fighting cells) or the central nervous system (brain and spinal cord) is less common.
- Recurrent – Recurrent disease means that the cancer has come back (recurred) after it has been treated. It may come back in the tissues where it first started or it may come back in another part of the body. Click here for more information about the CHOC Recurrent Cancer Program.
Treatment for Ewing sarcoma:
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
The most common treatments for Ewing’s sarcoma are surgery, radiation therapy and chemotherapy.
- Surgery – Surgery may be used in certain cases to try to remove the cancer and some of the tissue around it. Surgery may also be used to remove any tumor that is left after chemotherapy or radiation therapy.
- Radiation therapy – This approach uses X-rays or other high-energy rays to kill cancer cells and shrink tumors. Radiation for the Ewing’s family of tumors usually comes from a machine outside the body (external beam radiation therapy).
- Chemotherapy – This uses drugs to kill cancer cells. Chemotherapy may be taken by pill or put into the body by a needle in a vein or muscle. Chemotherapy is called systemic treatment because the drugs enter the bloodstream, travel through the body, and can kill cancer cells throughout the body. Chemotherapy with more than one drug is called combination chemotherapy. For treating the Ewing’s family of tumors, surgery or radiation is often used to remove the local tumor and chemotherapy is then given to kill any cancer cells that remain in the body.
A supplement to the treatment options listed above is myeloablative therapy with stem cell support. Myeloablative therapy is a very intense regimen of chemotherapy designed to destroy all cells that divide rapidly. These cells include some blood cells and hair cells, as well as malignant cancer cells. Stem cells are self-renewing cells that create all of the other various types of blood cells. Stem cell support involves enriching the stem cells to increase the number of these important cells circulating in the blood after the chemotherapy has been given to kill the remaining tumor cells.
Additional treatment may include one, or more, of the following:
- 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)
Long-term outlook for a child with Ewing sarcoma:
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.
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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