Extraosseous Ewing Sarcoma
Extraosseous Ewing sarcoma is biologically similar to Ewing sarcoma arising in bone. Until recently, most children and young adults with extraosseous Ewing sarcoma were treated on protocols designed for the treatment of rhabdomyosarcoma. This is important because many of the treatment regimens for rhabdomyosarcoma do not include an anthracycline, which is a critical component of current treatment regimens for Ewing sarcoma. Currently, patients with extraosseous Ewing sarcoma are eligible for studies that include Ewing sarcoma of bone.
From 1987 to 2004, 111 patients with nonmetastatic extraosseous Ewing sarcoma were enrolled on the RMS-88 and RMS-96 protocols. Patients with initial complete tumor resection received ifosfamide, vincristine, and actinomycin (IVA) while patients with residual tumor received IVA plus doxorubicin (VAIA) or IVA plus carboplatin, epirubicin, and etoposide (CEVAIE). Seventy-six percent of patients received radiation. The 5-year EFS and OS were 59% and 69%, respectively. In a multivariate analysis, independent adverse prognostic factors included axial primary, tumor size greater than 10 cm, Intergroup Rhabdomyosarcoma Studies Group III, and lack of radiation therapy.
Two hundred thirty-six patients with extraosseous Ewing sarcoma were entered on studies of the German Pediatric Oncology Group. The median age at diagnosis was 15 years and 133 patients were male. Primary tumor site was either extremity (n = 62) or central site (n = 174). Sixty of 236 patients had metastases at diagnosis. Chemotherapy consisted of vincristine, doxorubicin, cyclophosphamide, and actinomycin (VACA); CEVAIE; or vincristine, ifosfamide, doxorubicin, and etoposide (VIDE). The 5-year EFS and OS were 49% and 60%, respectively. Five-year survival was 70% for patients with localized disease and 33% for patients with metastasis at diagnosis. OS in patients with localized disease did not seem related to tumor site or size. In a retrospective French study, patients with extraosseous Ewing sarcoma were treated using a rhabdomyosarcoma regimen (no anthracyclines) or a Ewing sarcoma regimen (includes anthracyclines). Patients receiving the anthracycline-containing regimen had a significantly better EFS and OS compared with patients receiving no anthracyclines.[54,55]
Cutaneous Ewing sarcoma is a soft tissue tumor in the skin or subcutaneous tissue that seems to behave as a less-aggressive tumor than primary bone or soft tissue Ewing sarcoma. Tumors can form throughout the body, although the extremity is the most common site, and they are almost always localized. In a review of 78 reported cases, some lacking molecular confirmation, the OS was 91%. Adequate local control, defined as a complete resection with negative margins, radiation therapy, or a combination, significantly reduced the incidence of relapse. Standard chemotherapy for Ewing sarcoma should be used for these patients because there are no data to suggest which patients could be treated less aggressively.[56,57]