What is Ewing sarcoma?
Ewing sarcoma is the second most common malignant (cancerous) bone tumor affecting children, adolescents and young adults, but it is still a rare disorder. Approximately 250 cases are diagnosed each year in the United States.
Ewing sarcoma is a cancer, which means it can spread to other organs or tissues in the body, most commonly starting with the lungs.
Most Ewing sarcoma tumors are found in teenagers, but the disease can also occur at a younger age. Caucasian children, particularly boys, are far more likely to have Ewing sarcoma than any other racial or ethnic group.
Causes of Ewing sarcoma in children
Ewing sarcoma is characterized by chromosome changes that occur after birth. In a process known as translocation, chromosomes 11 and 22 “swap” small pieces of each other. The result is an abnormal gene that can be detected with DNA testing.
It is not known why translocation occurs.
The cause of Ewing sarcoma is genetic — in that it comes from a person’s genes — but it is not inherited like some other childhood cancers. Parents can’t pass along the genetic changes associated with Ewing sarcoma to their children. The child’s own biological makeup and prenatal development will determine if he will develop Ewing sarcoma.
Signs and symptoms of Ewing sarcoma in children
The symptoms of Ewing sarcoma depend on the size and location of the tumor, as well as your child’s age and general health.
Indications may include:
- Pain, stiffness or tenderness at the site of the tumor
- Pain that gets progressively worse over time, and may radiate outward from the tumor site
- Pain that awakes the child from sound sleep
- Swelling or mass around the affected bone
- Decreased motor skills; including difficulty walking or limping
- Weak bones, which may lead to a fracture
- Weight loss
A Ewing sarcoma located near the spinal cord may cause back pain that radiates out through the arms or legs.
Testing and diagnosis for Ewing sarcoma in children
Some symptoms of Ewing sarcoma can be easily ignored as normal growing pains in children, which makes regular check-ups and referrals to specialists extremely important. Prompt diagnosis and identification of cancer is crucial to successful treatment and outcome.
If your child has been referred to an orthopaedic or oncology specialist, your child’s diagnostic evaluation begins with a thorough medical history and physical examination. A detailed neurological assessment may also be performed. This involves a series of questions and tests to check the brain, spinal cord and nerve function.
At Children’s Hospital of Philadelphia (CHOP), clinical experts use a variety of diagnostic tests to diagnose tumors, including:
- X-rays, which produce images of bones.
- Magnetic resonance imaging (MRI), which uses a combination of large magnets, radiofrequencies and a computer to produce detailed images of organs, soft tissues, muscles, ligaments and other structures within the body. Your child is exposed to no radiation during an MRI.
- Computed tomography (CT) scan, which uses a combination of X-rays and computer technology to examine bones and produces cross-sectional images ("slices") of the body.
- EOS imaging, an imaging technology that creates 3-dimensional models from two flat images. Unlike a CT scan, EOS images are taken while your child is in an upright or standing position, enabling improved diagnosis due to weight-bearing positioning.
- Radioisotope bone scan, which can help locate areas of abnormal growth.
- Positron emission tomography (PET) scan, which uses radioactive sugar injected into a vein and a scanner to make detailed, computerized pictures of areas of the body.
- Blood tests, which can help determine drug usage and effectiveness, biochemical diseases and organ function.
- Needle biopsy, which is a procedure where a doctor places a small needle through the skin and into the lesion to withdraw a small sample of the abnormal tissue. The tissue is analyzed to confirm any findings.
- Bone marrow aspiration, a procedure in which a small amount of bone marrow fluid and cells are obtained by a needle inserted into a bone to check for problems with any of the blood cells made in the bone marrow.
In addition to diagnosing the specific type of cancer, these tests will also help determine the size and location of the tumor, and stage of the cancer. All of this information is crucial in determining the best treatment option for your child.
Treatments for Ewing sarcoma in children
There are many treatment options available for bone and soft tissue tumors, and some children will need a combination of these therapies. At CHOP, experts at the Bone and Soft Tissue Tumor Program take a team approach to treatment. Orthopaedic, cancer and other specialists collaborate to provide your child with individualized care and the best possible outcomes.
Our program is led by Kristy L. Weber, MD, and Alexandre Arkader, MD, nationally renowned surgeons who specialize in treating bone and soft tissues tumors, limb-sparing surgery and reconstructive surgery.
Treatment for Ewing sarcoma always involves chemotherapy before and after surgery to target the primary tumor and cancer cells that may have already spread, but have not yet been detected. Chemotherapy refers to medicines that help fight cancer.
In most cases, chemotherapy is given to your child through an implantable venous port in his chest. The port remains in place for the duration of therapy to help your child avoid multiple needle sticks.
Surgery for Ewing sarcoma has two goals:
• To remove the tumor
• To restore function at the site of the tumor
About 90 percent of children with Ewing sarcoma can be treated with limb-sparing (also known as limb-salvage) and reconstructive surgery. CHOP surgeons regularly perform these complex surgeries and are constantly working to improve outcomes for children with the most difficult-to-treat tumors.
Limb-sparing surgery is performed under general anesthesia. It involves cutting out the tumor and a margin of health tissue surrounding it. Depending on the size and location of the tumor, as well as your child’s age and stage of growth, surgeons may use a variety of reconstructive methods to restore your child’s body function.
Reconstruction may include:
- Joint replacement if your child’s Ewing sarcoma is located on or near his knee, hip or shoulder. If your child is still growing, a modified joint replacement that can be expanded as your child grows, may be used.
- Allograft (cadaver bone) if your child’s tumor is in the middle of an arm or leg bone. This replacement bone serves as a structural filler — giving your child’s limb more strength and durability as his own bone grows around it.
- Free vascularized fibular grafting if your child’s tumor is in the thigh bone. This procedure includes moving one bone from your child’s lower leg to replace a diseased thigh bone. This may be done along or in conjunction with an allograft.
In about 10 percent of cases — because of the size or location of the tumor — Ewing sarcoma cannot be removed with limb-sparing surgery. In these rare situations, two surgical options exist:
- Amputation of the affected limb.
- Functional amputation (rotationplasty). Children’s Hospital of Philadelphia is one of very few hospitals offering this complex surgery in which the ankle assumes the function of a knee. Children can resume active lifestyles and have almost normal function.
After surgery for Ewing sarcoma, your child should expect to stay two to five days in the Hospital.
Though surgery for malignant tumors is highly effective, we understand that any surgery can be a stressful experience for children and families. At CHOP, we offer a wealth of resources about how to prepare your child for surgery and what to expect during surgery.
Additionally, we employ numerous best practices before, during and after surgery to decrease the risk of infection and increase positive outcomes. For more details about safety protocols at Children's Hospital of Philadelphia, see safety in surgery.
Depending on your child’s individual situation, radiation therapy may be an option to treat Ewing sarcoma. Radiation therapy uses high-energy waves such as X-rays to kill or shrink cancer cells.
Proton Therapy for Ewing Sarcoma
Children’s Hospital of Philadelphia, in collaboration with Penn Medicine, also offers proton therapy to children at The Roberts Proton Therapy Center.
Proton therapy is an innovative form of radiation treatment that is only available at very few hospitals across the nation. The greatest benefit of proton therapy is that it delivers most of its energy to a very narrow field at the location of the tumor — making it less damaging to the surrounding healthy tissue.
If surgery was performed, your child will be examined by the surgeon about 1 to 2 weeks after surgery, then again at three and six months post-surgery. If your child had reconstructive surgery, she may require long-term follow-up care to monitor the joint replacement, allograft or fibular grafting. Children who had a limb amputation or rotationplasty will need to be fitted with a prosthetic and routine adjustments as they grow.
Regular monitoring by trained clinicians is strongly encouraged to monitor for possible recurrence of the growth and manage any side effects of treatment.
Ewing sarcoma can reoccur — even after being successfully treated — so it is important for your child continue to be seen regularly by one of the physicians at the Bone and Soft Tissue Tumor Program.
During follow-up visits, X-rays and other diagnostic testing of the tumor site or other areas may be recommended to closely monitor your child’s health, check the reconstruction, and make sure there is no recurrence.
Follow-up care and ongoing support and services are available at our Main Campus and throughout our CHOP Care Network. Our team is committed to partnering with parents and referring physicians to provide the most current, comprehensive and specialized care possible for your child.
If your child needs continued monitoring into adulthood, she can continue to see some of the same doctors who treated her. CHOP’s Bone and Soft Tissue Tumor Program works closely with Penn Medicine. For families who live farther away and need continued monitoring, our clinical professionals will help your child transition to adult care near home.
Children's Hospital of Philadelphia has an excellent track record of improving the quality of life for children diagnosed with Ewing sarcoma.
As with any cancer, prognosis and long-term survival can vary greatly from child to child, however. Prompt medical attention and aggressive therapy are important for the best prognosis.