Clinical prognostic factors in pediatric Ewing sarcoma.

Abstract

10052 Background: Treatment of Ewing sarcoma necessitates coordinated multi-disciplinary care that includes chemotherapy, surgery, and/or radiation. In developed countries, patients with localized disease have an overall survival of 70-80%, compared to 20-30% for those with metastases. The outcome of children with Ewing sarcoma in less developed countries has not been adequately described. We analyzed prognostic factors for Ewing sarcoma patients treated at a single institution in Lebanon, a developing country with available multidisciplinary treatment modalities. Methods: We reviewed characteristics and outcome of 42 pediatric patients treated at a multidisciplinary cancer center in Lebanon, between January 1999 and October 2012. Kaplan Meier curves were generated to estimate survival. Results: Median age at presentation was 10 years (range 1-18), and median follow-up was 41 months (range 8-110). Commonly affected primary sites included the extremity (36%, n=15), chest wall (19%, n=8), and pelvis (14%, n=6). Tumor size was ≥ 8cm in twenty (47.6%) patients. Thirty-two patients (76%) had localized disease, and ten (24%) had metastatic disease. All patients received 14 cycles of chemotherapy, with VDC alternating with IE. Local control was surgery alone (29%, n=12), radiotherapy alone (33%, n=14), or combination (38%, n=16). For patients with localized disease, the 5-year OS and DFS rates were 68% and 55% respectively, while for metastatic disease they were 28% and 25%. Tumor recurrence was local in 8 patients, distant in 8, and combined in 2. Factors associated with improved outcome included localized disease, extremity site, surgery, and timely local control. In multivariate analysis, timing of local control and metastatic disease were prognostically significant determinants of outcome. Conclusions: Treatment of childhood Ewing sarcoma in a multidisciplinary cancer center in Lebanon results in similar survival to that in developed countries when similar protocols are applied. Strong prognostic factors included stage (localized vs. metastatic), and timing of local control. Patients who had a local control time delay of more than 3 weeks fared worse, strongly suggesting that delays in local control should be actively minimized in Ewing sarcoma.