Ewing's+Tumor

These tumors most frequently metastasize through the blood stream. 25% of patients will have metastatic disease at diagnosis. [1] Most common sites for metastases are bone or bone marrow, and the lungs. Less than 10% of the patients have positive lymph nodes.[1] Other common sites involve visceral organs. [1] 75-80% of patients present with localized disease while 20-25% have metastases to lung, bone, or bone marrow. Nearly all patients have micromets at diagnosis. [1] || • Low-G1 (early stages I and II) • High-G2 (late stages IIB and III) [1] ||
 * **Epidemiolgy:** || Ewing sarcoma of the bones occurs predominantly in patients between the ages of ten and twenty years old. It may present as early as infancy and as late as the fourth and fifth decades of life. It is more common in Caucasians than Asians or African Americans. Also, the disease is seen more frequently in males than females.[1,2] ||
 * **Etiology:** || The main cause of Ewing sarcoma is still unknown but genetics plays a big role. The genetic alteration between chromosomes can cause cells to become cancerous. In Ewing sarcoma, the translocation between chromosomes 11 and 22 is often seen. This fuses the EWS gene to the FLI1 gene, which causes abnormal growth of the bones. [2] ||
 * **Signs & Symptoms:** || The most common presenting symptoms are pain and swelling at the site of the lesion. A palpable mass is seen in most cases indicating that the tumor is locally advanced and involves surrounding tissues. Other symptoms include shortness of breath, fever, weight loss, and fatigue.[2] ||
 * **Diagnostic Procedures:** || Plain radiographs and CT/MRI scans are used to view the appearance of bone abnormality and soft tissues involvement. A bone scan should also be obtained to detect asymptomatic skeletal metastases. An open biopsy is also an important diagnostic procedure.[1] ||
 * **Histology:** || Characterized by small, blue round cells and minimal mitotic activity and have characteristics of both mesodermal and ectodermal origin. ||
 * **Lymph node drainage:** || Lymph node metastasis is uncommon. ||
 * **Metastatic spread:** || MET SPREAD:
 * **Grading:** || Grading is determined to be:
 * **Staging:** || Enneking Staging System for Bone Sarcomas [1]

Grade Low Grade (G1) • Parosteal osteosarcoma • Endosteal osteosarcoma • Secondary chondrosarcoma • Fibrosarcoma, low grade • Atypical malignant fibrous histiocytoma • Giant cell tumor • Adamantionoma

High Grade (G2) • Classic osteosarcoma • Radiation-induced sarcoma • Paget’s sarcoma • Primary chondrosarcoma • Fibrosarcoma • Giant cell sarcoma

Local Extent Intracompartmental (T1) • Intraosseous • Parosseous • Intrafascial

Extracomplartmental (T2) • Soft tissue extension • Extrafascial or deep fascial extension

Distant Metastases M0: no distant metastases M1: distant metastases present ||
 * **Radiation side effects:** || Due to the radiation treatment of the femur most often two thirds of the patient population experience shortening of at least two centimeters and one third of the patients experience pathologic fractures. When patients receive a dose less than 60Gy their chance for developing second malignancies is seen at a rate of 0% to 1%. [1]

Radiation side effects are increased when the patient is being treated with concurrent chemotherapy. Radiation side effects include: erythema, fever, neutropenia, mucositis, nausea, vomiting, and diarrhea. Younger patients may experience chronic effects to the bone which may cause a delay in growth. A patient may develop scolitis when radiation is used to treat the vertebral bodies.

Another symptom may be a heightened sensitivity to chronic infection, fracture, and necrosis. The development of second malignancies is also a concern. [1] || Female gender, quick diagnosis (within 1 month of onset of symptoms), tumors in the distal long bones, and high lymphocyte count are all favorable prognostic factors. The site with the worst prognosis is pelvis, followed by proximal bones, such as the humerus or femur. [1] || Good results have been seen with the combined adjuvant radiation and chemotherapy. The chemotherapy regimen is VAC-ADR, combined with 45 Gy radiation to the primary tumor. [1] Typical doses are 45 Gy to the entire bone, with two 5Gy boosts to the tumor, with a 5 cm margin and a 1 cm margin, respectably. [1]
 * **Prognosis:** || Size of the primary tumor at the time of diagnosis is the most important prognostic factor, aside from metastasis. Other factors include the site and presence of honeycombing.
 * **Treatments:** || Surgery is the treatment of choice for lower extremity lesions, with amputation being reserved for local failures after radiation.

Radiation doses following 12 week induction chemo: Radiation alone: Initial port 45 Gy with boost to 55.8 Gy in 1.8 Gy fractions. Port is tumor plus 2 cm margin. Gross residual surgery and radiation: Initial port to 45 Gy with boost to 55.8 Gy in 1.8 Gy fractions. Port is tumor before resection plus 2 cm margin. Microscopic residual or marginal resection and radiation: Initial port to 45 Gy with boost to 50.4 Gy in 1.8 Gy fractions. [1] || [2] Hoppe TR, Phillips LT, Roach M. //Leibel and Phillips Textbook of Radiation Oncology.// 3rd Edition. Philadelphia, PA: Elsevier; 2010. [3] The Use of Normal Tissue Tolerance Doses into Linear Quadratic Equation to Estimate Normal Tissue Complication Probability. Sanchez Cancer Society. http://www.rooj.com/Radiation%20Tissue%20Tolerance.htm. Accessed June 30, 2012. ||
 * **TD 5/5:** || Femoral head and neck: 52 Gy [3] ||
 * **References** || [1] Chao C. //Radiation Oncology Management Decisions.// 2nd ed. Philadelphia, PA: Lippincott Williams and Wilkins; 2002.

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