Ewing Sarcoma

Ewing sarcoma is a cancer that occurs primarily in the bone or soft tissue. Ewing sarcoma can occur in any bone, but it most often is found in the hip bones, ribs, or 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 1 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 seem 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 most 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. Less often, there is an exchange of DNA between chromosome #22 and another chromosome that leads to the EWS gene being turned on. The exact mechanism remains unclear, but this important discovery has led to improvements in diagnosing Ewing sarcoma.

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
• Fever
• Weight loss, decreased appetite
• Fatigue
• Paralysis and/or incontinence (if the tumor is in the spinal region)
• Symptoms related to nerve compression from tumor (for example, numbness, tingling, or paralysis)

The symptoms of Ewing sarcoma may resemble other conditions or medical problems. Always consult your child's doctor for a diagnosis.

How is Ewing sarcoma diagnosed?

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 that 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 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 see if the tumor has spread to 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 horizontal, or axial, 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 (but often not quite as detailed as MRI scans).
  • 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 see if the cancer has spread to the bone marrow.

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 child's doctor based on:

• Your child's age, overall health, and medical history
• Location and 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:

• Surgery to remove the tumor
• Chemotherapy
• Radiation therapy
• Amputation of the affected arm or leg
• Resections for metastases (for example, 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

In general, the long-term outlook is much better if the cancer is still localized in the area where it started than if it has spread (metastasized) to other parts of the body. But 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, such as second malignancies, can occur in survivors of Ewing sarcoma. New methods are continually being discovered to improve treatment and to decrease side effects.