Comparison of soft tissue Ewing's sarcoma and peripheral neuroectodermal tumor.

Thirty-four cases with either extraskeletal Ewing's sarcoma (21 patients) or malignant peripheral neuroectodermal tumor of the soft tissues (13 patients) were reviewed retrospectively. The patients were treated between 1964 and 1991. Followup periods averaged 7.2 years for patients with peripheral neuroectodermal tumors and 10.4 years for patients with Ewing's sarcoma (minimal followup of 2 years). There were no significant differences in patient's age, gender, tumor location, and stages on presentation between patients with Ewing's sarcoma and those with malignant peripheral neuroectodermal tumor of the soft tissue. All but 2 patients underwent surgery for tumor resection. Adjunctive therapy (radiation or chemotherapy or both) was administered in 95% of the patients with Ewing's sarcoma and in 85% of the patients with peripheral neuroectodermal tumors. The 5-year overall survival was 50% for Ewing's sarcoma and 44% for peripheral neuroectodermal tumor. The 5-year disease free survival was 33% for both types of tumors. Survival rates were higher for Stage III compared with Stage IV disease for both types of tumors. There was a tendency for better outcome after complete surgical tumor resection. Survivors tended to be of a younger age at the time of tumor diagnosis. The results suggest that from a clinical perspective, these 2 tumors are quite similar.