Ewing’s sarcoma is a form of bone cancer that primarily affects children and young adults (average age is 13 years). It represents about 10% of primary bone tumors. Extra -skeletal Ewing’s sarcomas are very rare. This is a rare malignant tumor affecting three people per million of world population per year (3/1.000.000). It mainly affects young patients, with 90% of patients less than 20 years and a median age of 14 years.
This bone tumor is more common in teenage boys and a lot more common in white subjects than in black. Cells suspected to be responsible are those of Mesenchymal stem cells (MSCs), cells traditionally found in the bone marrow which serves as connective tissue to support other tissues. The risk of metastasis is high in cases of Ewing’s sarcoma. At diagnosis, 25% of patients may present with metastasis: 40% lung cancer, 30% other bone cancers (including the spine), 10% in bone marrow. Given the rarity of this disease and its severity, the treatment and management must take place in a highly specialized medical service center.
Ewing Sarcoma Causes
The pathophysiologic root of Ewing’s sarcoma is now well known. The mechanism most often found is a translocation between chromosomes 11 and 22 responsible for the occurrence of a protein fusion of EWS gene of chromosome 22 to the FLI1 gene of chromosome 11. This anomaly is found in 85% of Ewing tumor cases. For the remaining 15 %, there is a translocation between chromosomes 11 and 22 leading to the synthesis of an abnormal protein called EWS- ERG (EWS-ERG Gene Fusion). In both cases the abnormal protein leads to continuous activation of membrane IGF-1 receptor, which is responsible for cellular proliferation.
During teenage time, at the time of the growth spurt, normal cells are subjected to an intense signaling by growth hormone and IGF (insulin -like growth factor). In Ewing’s tumor, these cells lose their ability to be regulated by IGF thus resulting in uncontrolled proliferation which is the main characteristic of cancer.
Ewing Sarcoma Symptoms
Ewing Sarcoma Symptoms are mostly typical to any bone cancer. The tumor can develop anywhere in the body, but mainly in the bones of the lower limbs: femur, tibia, and fibula; as well as in the pelvis. The humerus and ribs are other particularly affected bone.
The most common symptoms are swelling of the affected area, as well as pain when walking. When the tumor is located in the ribs, the patient complains of a painful mass. Ewing Sarcoma tends to cause metastasis. In fact, in about 30% of patients the cancer is already metastasized to the lungs and bone marrow when detected.
In summary, common signs and symptoms of bone cancer, Including Ewing’s sarcoma, include:
- Broken bone
- Bone pain
- Swelling and tenderness near the cancer site
- Unintended weight loss
You need to see a doctor IMMEDIATELY if you or your child Develops any of These signs and symptoms above.
Ewing Sarcoma Treatment
Ewing Sarcoma Treatment is not unique for all patients. The quality of treatment is based primarily on a support in a highly specialized oncology service center. At all stages of the disease, using a good chemotherapy protocol allows the patient to receive the most appropriate treatment to survive the disease.
The treatment is usually done as follows: first chemotherapy to reduce the size of the tumor and any metastases and surgery of the tumor and its metastatic potential. Laboratory analysis of the tumor is used to evaluate the effectiveness of the initial chemotherapy. This is a very important during and after the treatment. If surgery is not possible it may be replaced by radiation therapy. The treatment is concluded with maintenance chemotherapy. The nature of the chemo agents used depends on the initial size of the tumor, the ability to completely operate the tumor and metastasis and outcome of chemotherapy performed before surgery. Therapeutic intensification with autograft may be necessary if the tumor is very large at the start or if it has decreased slightly with chemotherapy.
Chemotherapy – The following drugs are usually effective in Ewing’s sarcoma treatment: vincristine, doxorubicin, actinomycin, cyclophosphamide, Ifosfamide, adriamycin…
Surgery – in Ewing’s sarcoma treatment, the surgical procedure is performed to remove the entire cancer from the bone. Depending on the tumor, the surgery aims at removing the affected limb; removing the cancer, but spare the limb; or getting rid of cancerous tissue for cancer that doesn’t affect the limbs.
Radiation Therapy (radiotherapy) – radiotherapy may be recommended in patients with in Ewing’s sarcomas that are not operable (can’t be removed with surgery). In Ewing’s sarcoma treatment, Radiation therapy may also be used after surgery to kill remaining cancer cells. Radiation therapy is also used to reduce signs and symptoms in patients with advanced bone cancer.