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 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 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 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 for no apparent reason after they are born.
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 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 (for example, numbness, tingling, or paralysis)
The symptoms of Ewing sarcoma may resemble other medical conditions or problems. Always consult your doctor 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:
X-rays. A diagnostic test that 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 often 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.
Bone marrow aspiration/biopsy. A procedure that involves removing a small amount of bone marrow fluid and tissue, usually from part of the hip bone, 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 doctor based on:
Your age, overall health, and medical history
Location and 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
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 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, but in metastatic disease, long-term survival is around 25 percent. 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, 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.