Ewing sarcoma facts for kids
Quick facts for kids Ewing sarcoma |
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| Synonyms | Ewing's sarcoma, Peripheral primitive neuroectodermal tumor and Askin tumor (not recommended), Ewing sarcoma family of tumors |
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| Micrograph of metastatic Ewing sarcoma (right of image) in normal lung (left of image). PAS stain. | |
| Pronunciation | |
| Symptoms | Swell and pain near the tumor |
| Complications | Pleural effusion, paraplegia |
| Usual onset | 10 to 20 years old |
| Causes | Unknown |
| Diagnostic method | Tissue biopsy |
| Similar conditions | Osteosarcoma, neuroblastoma, osteomyelitis, eosinophilic granuloma |
| Treatment | Chemotherapy, radiation therapy, surgery, stem cell transplant |
| Prognosis | Five-year survival ~ 70% |
| Frequency | 1 per 1 million people (US) |
Ewing sarcoma is a type of cancer that usually starts in bones or soft tissues. It often causes swelling and pain where the tumor is. Sometimes, people might also have a fever or a bone fracture (break). This cancer most commonly begins in the legs, pelvis (hip bones), or chest wall.
In about 1 out of 4 cases, the cancer has already spread to other parts of the body when it is found. Complications can include fluid around the lungs (pleural effusion) or paraplegia (not being able to move your legs).
Ewing sarcoma is a type of "small round cell sarcoma." Doctors don't know exactly what causes it. Most cases seem to happen by chance. Sometimes, a small change in a person's DNA (called a germline mutation) might be involved. Often, the main reason is a genetic change called a reciprocal translocation, where parts of two different chromosomes swap places. To diagnose it, doctors take a small sample of the tumor (tissue biopsy).
Treatment for Ewing sarcoma often involves chemotherapy (medicine to kill cancer cells), radiation therapy (using high-energy rays), surgery, and sometimes a stem cell transplant. Scientists are also looking into targeted therapy and immunotherapy. About 70% of people with Ewing sarcoma are still alive five years after diagnosis. However, many things can affect this number.
James Ewing, a doctor, first identified this type of cancer in 1920. It affects about one in a million people each year in the United States. Ewing sarcoma is most common in teenagers and young adults. It makes up about 2% of all childhood cancers. It is more common in Caucasians than in African Americans or Asians, and more common in males than females.
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What are the Signs and Symptoms of Ewing Sarcoma?
Ewing sarcoma is more common in males than females (about 1.6 males for every 1 female). It usually appears in childhood or early adulthood, most often between ages 10 and 20.
This cancer can grow anywhere in the body. However, it is most often found in the pelvis and the large, long bones, especially near the growth plates. The middle part of the femur (thigh bone) is the most common spot. The tibia (shin bone) and humerus (upper arm bone) are also common.
About 30% of people already have cancer that has spread when they are diagnosed. Also, 10–15% of people have a bone break when the cancer is found. People with Ewing sarcoma usually feel a lot of bone pain.
Other signs and symptoms can include fevers that come and go, feeling tired (anemia), and other signs that your body is fighting something.
The Bone Cancer Research Trust (BCRT) says the most common symptoms are pain in one area, swelling, and bone pain that comes and goes. Swelling is easier to see if the cancer is on a bone close to the skin. If it's deeper in the body, like in the pelvis, the swelling might not be visible.
How Do Genes Play a Role in Ewing Sarcoma?
Changes in genes can cause cells to become cancerous. Most cases of Ewing sarcoma (about 85%) happen because of a specific genetic change. This change is a swap between parts of chromosomes 11 and 22. This swap is called t(11,22).
This swap joins two genes: the EWSR1 gene from chromosome 22 and the FLI1 gene from chromosome 11. When these genes join, they create a new, unusual protein called EWS-FLI1. This new protein can make cells grow in a way they shouldn't, leading to cancer.
How is Ewing Sarcoma Diagnosed?
Doctors make a final diagnosis by looking at the tumor under a microscope (histomorphologic findings), using special stains (immunohistochemistry), and checking for genetic changes (molecular pathology).
Ewing sarcoma is a type of "small-blue-round-cell tumor." Under a microscope, its cells often look clear because they contain glycogen. Special stains like PAS stain can show this glycogen. A common test for Ewing sarcoma is for a protein called CD99, which is found on the cell membrane. However, since CD99 can be found in other tumors too, doctors use other tests to confirm the diagnosis.
The most common genetic change, found in about 90% of Ewing sarcoma cases, is the t(11;22)(q24;q12) translocation. This creates the fusion of the EWSR1 gene with the FLI1 gene.
Doctors also consider other similar tumors when diagnosing Ewing sarcoma. These include lymphoma, a type of rhabdomyosarcoma, and desmoplastic small round cell tumor.
Medical Imaging for Diagnosis
When doctors take X-rays, Ewing sarcoma often looks like many holes in the bone, giving it a "moth-eaten" look. This is because the tumor is destroying the bone. The outer layer of the bone (periosteum) might also be pushed away as new bone grows on top of the tumor. This can create a classic sign called the Codman triangle. Sometimes, the bone layers can look like an "onion peel" on the X-ray. X-rays are helpful for the first check-up.
Magnetic resonance imaging (MRI) is usually used for checking malignant tumors. An MRI shows the full size of the tumor in the bone and soft tissue. It also shows how the tumor relates to nearby body parts, like blood vessels. Sometimes, a special dye called Gadolinium is used, but it's not always needed. Some doctors think it might help see how much of the tumor is dying, which can show how well treatment is working.
Computed axial tomography (CT) scans can also show how far the tumor has spread outside the bone, especially in the skull, spine, ribs, and pelvis. Both CT and MRI scans can be used to see how the tumor responds to radiation or chemotherapy. Bone scintigraphy (a type of scan) can also track how the tumor responds to treatment.
Sometimes, with tumors like Ewing sarcoma, the bone might look almost normal on X-rays. But the tumor can still be growing inside the bone. These tumors can also have a large soft-tissue mass even if there's not much bone damage visible on X-rays.
How is Ewing Sarcoma Treated?
Almost everyone with Ewing sarcoma receives chemotherapy (a mix of medicines like vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide). They also get local treatment, which means surgery or radiation to the tumor area. Doctors use a strong approach because even if the cancer seems to be only in one place, it often has spread without showing symptoms.
Surgery might involve saving the limb or, in some cases, amputation. If cancer is confirmed during a biopsy, the entire tumor might be removed right away. How long treatment lasts depends on where the tumor is and how far it has spread. Chemotherapy can be as short as six treatments over three-week cycles. However, most people have chemotherapy for 6–12 months and radiation therapy for 5–8 weeks.
Radiation therapy is used for tumors that are in one place. This type of tumor is very sensitive to radiation, sometimes described as "melting like snow." But the main problem is that it can come back later.
Newer treatments are being studied, such as Antisense oligodeoxynucleotides, which try to stop the cancer-causing protein from being made. Also, a medicine called fenretinide has shown promise in killing Ewing sarcoma cells in lab tests and slowing tumor growth in mice.
For children with cancer, proton therapy (a type of radiation) can deliver the right dose to the tumor. It causes less damage to healthy tissues nearby compared to regular radiation.
What is the Prognosis for Ewing Sarcoma?
Doctors try to figure out if the cancer is only in one place or if it has spread. The most common places for it to spread are the lungs, other bones, and the bone marrow. Less common places include lymph nodes, the liver, and the brain.
Whether the cancer has spread is the most important factor in how well someone will do. If the cancer has spread when it's found, the chance of surviving five years is about 30%. If it has not spread, the chance is about 70%.
Another important factor is where the main tumor is. Tumors closer to the center of the body (like in the pelvis or sacrum) are harder to treat than tumors farther away. Other things that can mean a poorer outlook include a very large tumor, being older than 18 when diagnosed, and high levels of a substance called lactate dehydrogenase (LDH).
For cancer that is only in one place, the five-year survival rate is over 70% after treatment. Before doctors used many different chemotherapy drugs, less than 10% of people survived long-term. Now, with a mix of chemotherapy, radiation, and surgery, long-term survival rates are over 50% in most hospitals. Some sources say it's 25–30%.
Research has also shown that two proteins, CXCR4 and CXCR7, can help predict how well someone will do. People with low levels of both proteins have the best chance of long-term survival (over 90% at five years). Those with very high levels have a lower chance (less than 30% at five years). A recent study also suggested that another protein called SOX2 can help find patients who are at high risk for the tumor coming back.
How Common is Ewing Sarcoma?
Ewing sarcomas make up about 16% of all primary bone cancers. In the United States, they are most common in teenagers. The rate is about 0.3 cases per million children under 3 years old, and as high as 4.6 cases per million in teenagers aged 15–19. Almost 80% of patients are under 20 years old. It is not common in children younger than 5 or adults older than 30.
Around the world, the average number of cases is less than 2 per million children each year. In the United Kingdom, about six children are diagnosed each year, mostly males in early puberty. Because it's often diagnosed during teenage years, some wonder if there's a link between puberty and the start of this disease, but no research has confirmed this.
In Wake Forest, North Carolina, three unrelated teenagers were diagnosed with Ewing sarcoma in 2011. All three attended the same temporary classroom. A fourth teenager nearby was diagnosed in 2009. The chances of this happening are considered very unusual. Ewing sarcoma is about 10 to 20 times more common in people of European descent compared to people of African descent.
Ewing sarcoma is the second most common bone cancer in children and teenagers. The outlook is not good for about 70% of initial diagnoses, and for 10–15% of cases where the cancer comes back.
Images for kids
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Micrograph of metastatic Ewing sarcoma (right of image) in normal lung (left of image). PAS stain.
See also
In Spanish: Sarcoma de Ewing para niños
