Ewing sarcoma is a form of bone cancer that usually affects children and adolescents.

Ewing sarcoma can be very aggressive, but the cells tend to respond well to radiation therapy. Ideally, doctors will diagnose the cancer before it has spread.

According to the National Library of Medicine, an estimated 250 children in the United States receive a diagnosis of Ewing sarcoma each year.

In this article, learn more about Ewing sarcoma, including the symptoms, causes, and treatment options.

a doctor checking for a Ewing sarcoma in a teenage girls leg. Share on Pinterest
Ewing sarcoma commonly occurs in the legs, chest wall, or pelvis.

Ewing sarcoma is a rare type of cancer that usually starts in the bone — typically in the pelvis, chest wall, or legs — and occurs mostly in children and teenagers.

Dr. James Ewing first described Ewing sarcoma in 1921. He identified cancer cells that looked different than the cells in osteosarcoma, another type of bone tumor.

Doctors may also refer to this cancer type as the Ewing family of tumors. These tumors have distinct cells that usually respond well to radiation treatments.

This rare cancer type accounts for just 1.5% of all childhood cancers and is the second most common bone cancer type in childhood, after osteosarcoma.

Although researchers are unsure why some people develop Ewing sarcoma, they have identified mutations in certain genes in the tumor cells that cause this cancer.

These include the EWSR1 gene on chromosome 22 and the FLI1 gene on chromosome 11.

These genetic mutations occur spontaneously during a person’s lifetime. The individual does not inherit them from a family member.

There are no known risk factors for Ewing sarcoma that make one person more likely than another to develop this cancer.

Ewing sarcoma can cause the following symptoms:

  • a bone that breaks easily or without a clear cause
  • fevers
  • a lump under the skin that is usually soft and warm to the touch
  • pain in the affected area, such as the arms, back, chest, legs, or pelvis
  • swelling in the affected area

An estimated 87% of Ewing sarcomas are sarcoma of the bone. The other types form in the soft tissues, such as cartilage, that surround the bones.

Ewing sarcoma can spread to other areas of the body. Doctors call this process metastasis.

Areas that the cancer can spread to include other bones, bone marrow, and the lungs.

Doctors categorize Ewing sarcoma as one of three types according to its extent:

  • Localized Ewing sarcoma: The cancer has not spread to other body parts but may have spread to other nearby lymph nodes.
  • Metastatic Ewing sarcoma: The cancer has spread to other parts of the body, such as the lungs, bone marrow, or other bones.
  • Recurring Ewing sarcoma: A person has had Ewing sarcoma before, and it has come back.
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A doctor may order an X-ray if they suspect Ewing sarcoma.
Image credit: Redini F & Heymann D, 2015.

Before diagnosing Ewing sarcoma, a doctor will take a person’s full medical history and ask them what symptoms they are having, when they noticed them, and what makes them better or worse. They will also perform a thorough physical exam, focusing on the area of concern.

A doctor will usually recommend an imaging study to view the bone or bones. These tests include:

If it looks as though a tumor may be present, a doctor will perform a biopsy, which involves taking a sample of bone tissue. They will send this tissue to a laboratory, where a specialist called a pathologist will check it for the presence of cancerous cells.

A doctor may also order blood tests, a bone marrow biopsy, and other scans when necessary. These tests can help determine whether the cancer has spread to other locations.

A doctor will work with a team of cancer specialists and surgeons to recommend and implement particular treatments.

Possible treatments for Ewing sarcoma include:

  • Chemotherapy: Chemotherapy uses medications to kill off multiplying cancer cells. It is often the first treatment for Ewing sarcoma. A person will usually receive chemotherapy for 6 to 12 months.
  • Radiation: Radiation therapy involves killing cancerous cells with high energy radiation treatments. Sometimes, doctors prescribe radiation therapy to shrink a tumor or keep it from spreading.
  • Surgery: In some cases, a doctor will recommend surgically removing the tumor. If a doctor has to take out a lot of bone, they may recommend replacing it with a bone graft or artificial bone.
  • Stem cells: Doctors may use stem cell transplants from a donor’s bone marrow to encourage healthy bone cell growth.

Doctors may use a combination of treatments depending on how far the cancer has spread and a person’s overall health.

Research into new treatments for Ewing sarcoma is ongoing. Some doctors may inform their patients about clinical trials, which help test new treatments.

Possible complications of Ewing sarcoma include:

  • pleural effusion, which is the buildup of fluid in the lung tissue layers
  • problems breathing
  • weakness or paralysis of muscles

If Ewing sarcoma has spread to other areas of the body, it can be life threatening. For this reason, it is vital for a doctor to evaluate any symptoms as quickly as possible.

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The outlook tends to be better when the cancer remains localized.

According to the American Academy of Orthopaedic Surgeons, an estimated two-thirds of people in whom cancer has not spread to other areas of the body survive at least 5 years after their diagnosis.

People who are more likely to have positive outcomes include those who have:

  • cancer that has not spread
  • cancer that responds well to chemotherapy
  • a tumor that occurs in the arms or legs, as the pelvis is usually harder to treat
  • a tumor that a surgeon can completely remove

The likelihood of successful treatment is different for every individual, so people should speak to a doctor about their or their child’s expected outlook.

Ewing sarcoma is a rare type of cancer that mostly affects young people.

When doctors detect it early enough, the condition usually responds well to treatment.

Anyone who notices signs or symptoms of Ewing sarcoma, such as a bone that breaks for no apparent reason or a painful lump or swelling, should speak to a doctor.