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 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 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 is a very rare cancer in adults. However, Ewing sarcoma accounts for about one to two percent of childhood cancers. About 225 children and adolescents are diagnosed with Ewing sarcoma in the U.S. each year. 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.
What causes Ewing sarcoma?
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.
What are the symptoms of Ewing sarcoma?
The following are the most common symptoms of Ewing sarcoma. However, each individual may experience symptoms differently. Symptoms may include:
- 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 medical conditions or problems. Always consult your physician for a diagnosis.
How is Ewing sarcoma diagnosed?
In addition to a complete medical history and physical examination, diagnostic procedures for Ewing sarcoma may include the following:
- Multiple imaging studies, including the following:
- X-rays--A diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
- Radionuclide bone scans--Pictures taken of the bone with a special camera after a small amount of radioactive dye has been injected that is absorbed by bone tissue. These are used to detect tumors and bone abnormalities.
- 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 nearby soft tissues.
- 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 both horizontal and vertical cross-sectional images (often called slices) 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.
- Bone marrow aspiration/biopsy--A procedure that involves a small amount of bone marrow fluid and tissue to be taken, usually from part of the hip bone, to further examine the number, size, and maturity of blood cells and/or abnormal cells and to detect cancer 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.
Treatment for Ewing sarcoma:
Specific treatment for Ewing sarcoma will be determined by your physician based on:
- Your age, overall health, and medical history
- Extent of the disease
- Your tolerance of specific medications, procedures, or therapies
- Expectations for the course of the disease
- Your opinion or preference
Treatment may include:
- Surgery to remove the tumor
- Radiation therapy
- Amputation of the affected arm or leg
- 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 an individual with Ewing sarcoma:
It is unclear whether adults with Ewing sarcoma do as well as children. Some studies have suggested they do not, but these studies have been criticized because they used lower doses of chemotherapy than those used in children. Other studies have suggested that when treated aggressively, adults can do as well as children. In children with localized disease, cure rates are as high as 80 percent, and even in metastatic disease, nearly 50 percent cure rates have been reported. The individual patient 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
- Your age and overall health
- Your 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 person to person. Every individual is unique and treatment and prognosis is structured around your needs. Prompt medical attention and aggressive therapy are important for the best prognosis. Continuous follow-up care is essential for a person 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.