Validation of a Multi-modal Treatment Protocol for Ewing Sarcoma--a Report from the Polish Pediatric Oncology Group

Background: Ewing sarcoma (ES) is the second most common paediatric malignant bone tumor. Advances in multi-disciplinary care have resulted in significant improvement in cure rates over the last decades. However, the generalization of those results in countries traditionally excluded from large cooperative trials has yet to be demonstrated. We report the results of modern multi-disciplinary care for patients with ES in Poland.

Procedures: One hundred and thirty-two patients with ES were treated using modern multi-modal therapy during the period 2000-2009. Overall survival was estimated by Kaplan-Meier methods and compared using long-rank test and Cox models. Factors predictive of outcome in our setting were analyzed to identify distinct risk groups that could help identify areas for improvement.

Results: The median age at the time of diagnosis was 12.3 years. With a median follow-up of 5.0 years, the 5-year event-free survival (EFS) and OS estimates for localized disease were 54.88% and 68.29%, respectively. For patients with metastatic disease, 5-year EFS and OS estimates were 36% and 42%, respectively. There was no correlation between age and stage or site. Patients with localized, non-pelvic disease had better outcome than patients with axial tumors (71% vs. 44%, respectively, P = 0.00073). Treatment failure was associated with stage, pelvic primary, poor histological response, and type of local control.

Conclusions: Successful treatment of ES requires optimal systemic and local therapy. We were able to replicate the results of modern multi-modal protocols. Validation of current treatment protocols in countries with more limited cancer treatment resources is required.