Ewing’s sarcoma is a bone cancer that typically occurs in adolescents ages 10 to 20. Discovered by James Ewing in 1921, Ewing’s sarcoma is the second most common malignant bone tumor in youth, as well as the most lethal bone tumor.
Though the cell of origin remains unknown, it is usually present in the arms, legs, or thighbone. This cancer can also affect surrounding soft tissues and muscle, sometimes even spreading as far as the patient’s bone marrow or lungs.
With no known risk factors, causes or genetic prevalence, it is difficult to determine who will or will not develop Ewing’s sarcoma. Accounting for 30% of bone cancers in children, Ewing’s sarcoma will affect 1 in 50,000 teenagers. Patients generally have the following in common:
- Age: The average patient is between ages 4 and 15. Ewing’s sarcoma rarely develops in people over 30.
- Gender: After adolescence, males are more prone to develop Ewing’s sarcoma than females. (Before adolescence, the risk is equal.)
- Race: Ewing’s sarcoma predominantly affects white children.
Signs and Symptoms
Though each child’s signs and symptoms differ, they may include:
- Weight Loss
- Decreased Appetite
- Swelling and Redness: This may be present around the site of the tumor.
- Numbness, Tingling and/or Paralysis: These may result from nerve compression.
- Paralysis and Incontinence: These may result if a tumor exists in the spinal region.
Following a complete physical exam, medical history, and x-rays of the affected area, a potential Ewing’s sarcoma patient may have any number of the following diagnostic tests run:
- Bone Scan: Using nuclear imaging, the sites of pain or possible tumors will be examined to determine their causes.
- Computerized Tomography (CT) Scan: By using computers, this type of x-ray will give doctors a better look at the body than a regular x-ray. This is also used to look at a patient’s lungs to see if any cancer has spread to that region.
- Blood Tests: A complete blood count (CBC) is used to show any abnormalities present in the blood. A test for the levels of a specific enzyme, lactate dehydrogenase (LDH), as well as a test for the red blood cell sedimentation rate, may also be given.
- Magnetic Resonance Imaging (MRI): Instead of x-rays, this test uses magnets to create clearer images of the body. Using radio waves and computers, MRIs are used to produce better, more detailed images.
- Biopsy: The only way to be certain that cancer is present–as well as to be sure that the cancer is Ewing’s sarcoma–a biopsy involves removing a small part of the tumor for examination. If the tumor is small, a surgeon may be able to remove the entire mass in an excisional biopsy while the patient is under general anesthesia. It may also be possible to remove a small sample through a needle, without making an incision. The method used will vary on a case-by-case basis.
If Ewing’s sarcoma is discovered using the biopsy, other tests may need to be run in order to eliminate the possibility of other childhood cancers:
- Immunohistochemistry: In this test, a piece of the sample will be treated with antibodies to be examined under a microscope. This is done to check for substances that are unique to Ewing’s sarcoma cells.
- Cytogenetics: The chromosomes in the sample will be examined to determine whether or not pieces of one chromosome has broken off and attached to another, enabling the health care provider to distinguish between Ewing’s sarcoma and other cancers.
- Reverse Transcription Polymerase Chain Reaction (RTPCR): Analyzing the RNA of the patient with chemicals, this test is more sensitive than cytogenetics and can confirm the type of tumor as well as monitor recurrent cancer post-treatment.
- Bone Marrow Aspiration and Biopsy: A small amount of cells will be removed from the bone marrow (the spongy tissues located inside the bone). These are analyzed to check for cancer signs, sometimes periodically throughout a treatment. These tests take 15 to 20 minutes and include giving the patient a local anesthetic to numb the site prior to being given. Sometimes a general anesthesia is offered to put the patient to sleep for the procedure.
There are various treatments available for Ewing’s sarcoma. These include:
- Surgery: Tumors may be removed through surgery, sometimes followed after chemotherapy, which usually lasts around nine weeks. This can only be performed if the surrounding tissue and organs will not be damaged in the process.
- Radiation Therapy: This painless procedure, similar to x-rays, involves beaming high-energy x-rays at the cancer site to kill the cancer cells. This can damage the healthy cells in the area as well, but they can heal themselves and repair damage much more efficiently and effectively than the cancer cells.
- Chemotherapy: Using drugs to kill the cancerous cells, chemotherapy can be taken by a pill or injected into a vein or muscle. Sometimes a combination of multiple drugs may be used. This treatment usually follows surgery or radiation in Ewing’s sarcoma patients.
- Myeloablative Therapy: For patients with resistant or recurring disease, this therapy, including support from stems cells, may be used. It involves heavy dosages of chemotherapy accompanied by stem cell implantation to replace the cancerous and dying cells with healthy ones.
Treatment for Ewing’s sarcoma will depend on which stage the patient is in. There are two primary stages:
- Localized Tumor: These tumors are confined to the tissues in which they developed. Though they may affect surrounding tissue, such as muscle or tendons, they have not yet spread far from their original site of development. Localized tumors can be treated through chemotherapy combined with surgery, radiation therapy (with or without surgery), and chemotherapy following surgery, with or without a stem cell transplant.
- Metastatic Tumor: These tumors have spread from their original location to other parts of the body, such as the lungs or other bones, and sometimes, in rare instances, the lymph nodes and liver. Metastatic tumors may be treated with a combination of chemotherapy followed by surgery or radiation, or high-dose chemotherapy, possibly with radiation therapy and stem cell support.
Both stages may be treated with clinical trials of intensive chemotherapy and drug combinations.
Two-thirds of patients without a large spread of Ewing’s sarcoma will survive at least five years following treatment. Bone tumors are the third leading cause of death for children ages 10 to 14 in the United States.
There are no means of prevention.
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