Ewing sarcoma

What is Ewing sarcoma?

Ewing sarcoma is a very rare cancer that appears as a solid tumor, most often in children and teens. Most cases occur between ages 10 and 20. Only a small percentage of people with Ewing sarcoma are older than 20. Nearly everyone with this cancer is white.

Ewing sarcoma typically develops in bones, but it actually arises from a type of primitive nerve cell. That's why Ewing sarcoma can occur outside bones, in the body's soft tissues. When it does, it is called non-osseous Ewing sarcoma.

Ewing sarcoma usually develops in the pelvis, arms, legs, chest wall (including the ribs or shoulder blades), or spine. More rarely, it can occur in soft tissues. When diagnosed, about a quarter of Ewing sarcomas have spread (metastasized) to another part of the body. The most common sites for a metastasis are

• the lungs
• another bone
• the bone marrow.

Like other cancers, Ewing sarcoma is caused by abnormal cells that multiply out of control. The cells of Ewing sarcoma have a change in the chemical material (DNA) that the person inherited from his or her parents. This change, called a translocation, usually involves a rearrangement of DNA between two chromosomes. The problem, however, is not inherited. It develops after birth.

Ewing sarcoma does not seem to be related to

• exposure to radiation
• exposure to chemicals
• other environmental factors.

No one knows what causes the genetic change that leads to Ewing's sarcoma.

Symptoms of Ewing sarcoma

Symptoms of Ewing's sarcoma include

• persistent pain and swelling in an arm or leg or in the pelvis, which may occur at rest and may even awaken the person from sleep
• a firm lump on an arm or leg, sometimes with tenderness
• a limp (if the tumor affects the leg)
• difficulty breathing (if the tumor affects the ribs)
• fever
• weight loss.

In physically active children, the pain and swelling of Ewing sarcoma can be mistaken for symptoms of a sports injury. In those who have a fever, symptoms of Ewing sarcoma can be confused with those of a bone infection. As a result, diagnosing Ewing sarcoma may take time.

Diagnosing Ewing sarcoma

After reviewing your symptoms, your doctor will examine you and the painful area. Your doctor will check the area for warmth, redness, swelling, tenderness, limited motion, and any signs that a joint is involved. Blood and urine tests and an x-ray of the area usually follow the physical exam.

In most cases, the results of laboratory tests are normal because blood and urine tests can't confirm the diagnosis of Ewing sarcoma. However, the x-ray usually will show an abnormality consistent with Ewing sarcoma, or another problem such as bone destruction.

If your doctor finds x-ray evidence of a bone tumor, he or she will refer you to a hospital that has the facilities, personnel, and experience to treat bone cancer. There you will have further tests, such as magnetic resonance imaging (MRI) scans, to help determine whether the abnormal-looking area is in fact a tumor, or possibly bone damage caused by something else. An MRI can also help to see whether the tumor has invaded other structures.

After the tumor's location has been determined, you will have a biopsy to confirm the diagnosis of Ewing sarcoma. During a biopsy, a small amount of tissue is removed and examined in a laboratory.

You probably will have a chest x-ray, CT scan, and a radionuclide bone scan. A PET scan may be ordered as well. Along with a bone-marrow biopsy, these tests can show whether the cancer has spread to your lungs, other bones, or bone marrow.

Expected duration of Ewing sarcoma

Ewing sarcoma will continue to grow until it is treated. If it is not treated, this cancer can spread to the lungs and to other bones.

Preventing Ewing sarcoma

There is no way to prevent Ewing sarcoma.

Treating Ewing sarcoma

Ewing sarcoma is primarily treated with chemotherapy. Surgery and sometimes radiation will also be used. The choice of treatment depends on the size and location of the tumor, and on how much of the nearby tissue it had invaded.

Sometimes doctors use chemotherapy to shrink the tumor before surgery, which makes it easier to remove the tumor. Chemotherapy also lowers the chance that the cancer will come back, either in the original spor or in other parts of the body.

If treatment is successful, you will need follow-up visits with your doctor for many years. This is because Ewing sarcoma can return in the 10 years following the diagnosis. Also, if you received radiation therapy, a second cancer may develop where you received the radiation. You also may suffer late side effects from chemotherapy. Your doctors will periodically order

• blood tests to monitor blood counts and kidney function
• an echocardiogram to track heart function.

When to call a professional

Call your doctor if you or your child develops persistent or unexplained pain and swelling in a bone, with or without a fever.

Prognosis

With treatment, about 80% of patients diagnosed with localized Ewing sarcoma (meaning the cancer had not spread) are still alive after five years. The prognosis is better in children younger than age 15, and for those with tumors that are further down the arms and legs. People whose cancer has spread usually have a poorer prognosis.

Additional info

National Cancer Institute (NCI)
www.cancer.gov/

American Cancer Society (ACS)
www.cancer.org/

American Academy of Pediatrics (AAP)
www.aap.org/

American Society of Clinical Oncology
www.asco.org/