Pelvic ewing sarcoma. A retrospective analysis of 241 cases

BACKGROUND. This article reports on 241 patients each with pelvic Ewing sarcoma registered for studies in Germany, Austria, and the Netherlands from January 1, 1981, until January 31, 1994. One hundred sixty-four patients had localized disease and 87 had metastases at diagnosis (PMP). Eighty-four patients with localized disease were entered on protocol (PP) and 80 were followed (FP). METHODS. Statistics included an analysis of event free survival by the Kaplan-Meier method and a Cox regression analysis of factors influencing prognosis. RESULTS. In the Kaplan-Meier analysis, on February 1, 1995, the event free survival (EFS) rate was 32% at 12 years for all patients, 54% for PP, 25% for FP, and 13% for PMP. Cox regression analysis showed that response to chemotherapy, initial metastases, and less intense therapy were significant prognostic factors. Among patients who had surgery for local control, the histologic response to chemotherapy was analyzed in the surgical specimen and had a significant influence on survival: EFS 69% for PP with good response compared with 47% (P = 0.11) for patients with poor response, and for FP 56% versus 13% (P = 0.002). All PP with small tumors had relapse free survival, compared with 69% of patients with medium-sized tumors and 36% of patients with tumors larger than 200 mL (P = 0.006). The initial tumor volume was a significant predictor of survival. CONCLUSIONS. Combined modality treatment has resulted in definitive improvement of prognosis for patients with localized pelvic Ewing sarcoma. However the results for patients with metastases at diagnosis are still discouraging, and their treatment requires new approaches. Tumor load, responsiveness to chemotherapy, and adequate surgical margins are the major factors influencing the prognosis of patients with localized Ewing sarcoma of the pelvis.