All About Pediatric Ewing Sarcoma
What is Ewing sarcoma?
A sarcoma is a cancer of connective tissues, including bone, muscle, cartilage, and other tissue types. Ewing sarcoma is a specific type of sarcoma. It most often starts in bone, but can also start outside the bone, and is called "extraosseous." Unlike osteosarcoma (cancer of the bone), it tends to affect bones of the axial (central) skeleton (spinal column, pelvis, rib cage, etc.) about equally to the appendicular skeleton (long bones of the arms or legs). This article will focus on pediatric/young adult Ewing sarcoma. Learn more about adult sarcoma of the bone.
What causes Ewing sarcoma and am I at risk?
Ewing sarcoma is the second most common bone tumor in children but is still very rare. These tumors make up about 1% of all childhood cancers. There are an estimated 200 cases diagnosed every year in children and young adults in the US. About half of all cases occur in children/teens between the ages of 10-20. Ewing sarcoma occurs more in white (Caucasian) children/teens and is more common in boys than girls.
While Ewing sarcoma does not appear to be an inherited disease, some genetic changes in individual chromosomes could impact risk. Many individuals with Ewing sarcoma have chromosomal translocation-when small pieces of genetic material switch places within the tumor cell. Researchers have identified that this translocation can occur between chromosomes 11 and 22 as well as between 21 and 22, 7 and 22, and 17 and 22. This can cause the cancer cells to grow out of control. This genetic mutation develops over time and is present only in tumor cells.
How can pediatric Ewing sarcoma be prevented?
Children/teens with Ewing sarcoma usually do not have any risk factors. Because of this, there is no way to prevent it.
What screening tests are used?
There are no recommended screening tests for childhood cancer. A child/teen won’t be tested for Ewing sarcoma unless they are showing signs or symptoms of the disease.
What are the signs and symptoms?
Symptoms of Ewing sarcoma can include:
- Swelling, soreness or a lump/growth, usually in a bony area or the area surrounding the bone. This pain may come and go and can feel worse with exercise or at certain times of the day.
- A fracture (broken bone) that happens without an injury or trauma. This is called a pathologic fracture that is the result of the bone being weakened by the tumor.
How is Ewing sarcoma diagnosed?
The first step in diagnosing Ewing sarcoma is an X-ray of the painful area/bump or mass. If this X-ray looks like it could be a bone tumor, an MRI is performed. An MRI allows the healthcare team to get a better look at the growth and can help determine if a biopsy is needed. Imaging alone is not enough to definitively diagnose a bone cancer.
For this, a biopsy is needed. This is often done by an orthopedic surgeon. Once the tissue has been obtained, it is sent to pathologists who perform special tests on the specimen to make a definitive diagnosis. Ewing sarcoma has special features that help to confirm the diagnosis, including the appearance of the cells under the microscope, and usually, that specific genetic change in the tumor cells is present.
Once the diagnosis is confirmed, tests will be done to see if the cancer has spread (metastasized) to other parts of the body (metastatic disease), which occurs in about 20-30% of children. The most common metastatic sites for Ewing sarcoma (in descending order of frequency) are lungs, bone, bone marrow, or a combination of these sites. To assess for the presence of metastases, the following tests are often done:
- CT scan of the chest.
- Bone scan.
- Bone marrow aspirate & biopsy of both hips.
- PET scan.
How is Ewing sarcoma staged?
There is no official staging system for Ewing sarcoma. However, healthcare providers do classify Ewing sarcoma into two categories, which helps them to plan treatments:
- Localized disease: the tumor is limited to the primary site and adjacent lymph nodes.
- Metastatic disease: the tumor has spread to other organs in other parts of the body such as the lungs, other bones, or bone marrow.
How is Ewing sarcoma treated?
In children/teens where the disease is limited to the primary site, there are two main focus points in treatment:
- Control of the tumor at the primary site.
- Treatment targeted to micro-metastases. These are areas of microscopic disease that may have spread throughout the body but cannot be visualized with available imaging studies. These are presumed to be present in all patients based on the fact that in the past when treatment was with surgery alone, almost all children/teens relapsed with metastatic disease, even if surgery was effective in removing the primary tumor.
Treatment for Ewing sarcoma involves chemotherapy before and after surgery/radiation. Chemotherapy is the use of medications to kill cancer cells. Chemotherapy can be given in a number of ways including into a vein (IV), by mouth, into a muscle, or into the cerebrospinal fluid. Medications used in the treatment of Ewing sarcoma include vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide. Other medications will be given with the chemotherapy to prevent or minimize side effects. These include filgrastim/pegfilgrastim, which is a growth factor that stimulates the bone marrow to make more white blood cells in an attempt to prevent a low white blood cell count (called neutropenia).
After several cycles of chemotherapy, repeat imaging, usually an MRI, will be done. This is done to measure the response to the initial treatment and to plan for the next treatment steps for treating the primary tumor.
Both surgery and radiation (or a combination) can be used to successfully treat the primary tumor, but whenever possible, surgery is the preferred method. The type of surgical procedure used for primary tumor control depends on the location. If local control with surgery is not possible, or if surgery can not remove the tumor, radiation will be used. Radiation is effective in the treatment of Ewing sarcoma, and certain technologies, such as proton therapy, may be used to lessen its long-term risks. (will link)
After surgery/radiation, chemotherapy treatments will resume until the total treatment course is completed. The treatment lasts about 8-9 months.
Metastatic Ewing sarcoma is treated in a similar fashion as localized disease with chemotherapy, surgery, radiation, and then further chemotherapy treatments. However, areas of metastasis are dealt with on a site-by-site basis. If the initial cycles of chemotherapy successfully eliminate metastatic sites, no further site-specific treatment may be needed. However, if there is persistent metastatic disease after the first several cycles of chemotherapy, treatment of these areas with radiation (and sometimes surgery) may be attempted. This could include radiation therapy to the lung. Current clinical trials are investigating the role of radiotherapy to treat all metastatic sites of disease, sometimes with the use of stereotactic body irradiation.
Using very high doses of chemotherapy with autologous stem cell rescue (autologous transplant) is sometimes used for children with metastatic (or recurrent) Ewing sarcoma. How well this works is still unclear. This type of treatment is usually offered as part of a clinical trial.
What if Ewing sarcoma returns after treatment?
Management of recurrent/relapsed disease is highly specific to the individual patient. Factors including the length of time to relapse, location of relapse, number of sites of relapse, and previous treatment received will be taken into account to plan for additional treatment. This treatment may include a combination of chemotherapy (often with investigational agents), radiation, and surgery.
There are clinical research trials for most types of cancer, and every stage of the disease. Clinical trials are designed to determine the value of specific treatments. Trials are often designed to treat a certain stage of cancer, either as the first form of treatment offered or as an option for treatment after other treatments have failed to work. They can be used to evaluate medications or treatments to prevent cancer, detect it earlier, or help manage side effects. Clinical trials are extremely important in furthering our knowledge of the disease. It is through clinical trials that we know what we do today, and many exciting new therapies are currently being tested. Talk to your provider about participating in clinical trials in your area. You can also explore currently open clinical trials using the OncoLink Clinical Trials Matching Service.
Follow-up Care and Survivorship
The chemotherapy medications used in Ewing sarcoma can result in long-term problems with heart function, kidney function, fertility, and second cancers such as leukemia. Radiation can slow or stop growth in normal tissues that were in the area treated with radiation, or increase the risk of second cancers such as leukemia, other sarcomas, skin cancers, and others. Parents may want to talk with their child/teen’s team about the potential impact of treatment on their fertility (ability to have a child).
After treatment for childhood cancer, you will be followed closely to monitor for the cancer coming back, to manage ongoing side effects, and to transition to survivorship. At first, you will have frequent appointments with providers and have ongoing tests to monitor your health and possible recurrence of your cancer. As time goes on, these visits and testing will become less frequent. The oncology team will discuss the plan for follow up.
What can you do to live a healthy life after treatment? There is no supplement or specific food you can eat to assure good health, but there are things you can do to live healthier, prevent other diseases, detect cancers early and work with the social and emotional issues, including insurance, employment, relationships, sexual functioning, and fertility, that a prior cancer diagnosis sometimes brings with it. Your oncology team is there to support you and can help you find support resources.
It is important to have a plan for who will provide follow up care (an oncologist, survivorship doctor or primary care doctor). Talk with the team about developing a survivorship care plan or develop one using the Smart ALACC tool. Your child may benefit from being seen in a survivorship clinic. At a survivorship clinic, a provider can review your child's history and provide recommendations. You can contact cancer centers in your area to see if they have a survivor's clinic or search for a clinic on OncoLink's survivorship clinic list.
Resources for More Information
Sarcoma Foundation of America
The SFA raises money for sarcoma research and aims to raise awareness of sarcoma. The site has information for patients as well.
This website, started by a sarcoma survivor, is based on the mantra "guidance, education, and support". They also maintain a list of specialty centers.
A site maintained by Dr. Henry DeGroot, an orthopedic oncologist from the University of Massachusetts Medical School. It provides information on a comprehensive list of types of bone tumors in English and Spanish.
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Womer, RB et al. Chemotherapy for the treatment of localized Ewing sarcoma: a report from the Children's Oncology Group. Journal of Clinical Oncology. 2013; 30: 4148-4154.