Risks of recurrence and survival after relapse in patients with Ewing tumor

10012 Background: Ewing tumor treatment has resulted in long term survival rates of approx. 70% in localized, and 30% in metastatic disease. Survival following relapse has remained poor with survival rates well below 30%. Methods: All histological proven Ewing tumor patients from three consecutive GPOH trials since 1981 (CESS81 & CESS86 & EICESS92; N=1,549) were included to conduct a meta-analyses of time to and type of recurrence. The follow up has been recently updated in 2006 resulting in a maximum observation period of 25 years. The cumulative incidences of the types of first relapse excluding progress under therapy were computed with competing risk analysis. Multivariate stepwise regression analyses according to the Cox proportional hazard model researched the influences of time to and type of relapse on survival after relapse. Results: More than 70% of first recurrences occurred within 2 years, and 85% within 3 years from initial diagnosis. Most common relapses were systemic with a 3-year cumulative incidence of approx. 0.10 each for lung metastases, bone metastases and multisystem metastases including other sites, followed by local and combined relapses both with a 3-year cumulative incidence of approx. 0.05. Multivariate analyses identified both early (2.5 (p No significant financial relationships to disclose.