Abstract
BACKGROUND: A minority of patients with Ewing sarcoma present with regional lymph node involvement. We investigated if patient characteristics and outcomes differ between patients with Ewing sarcoma with and without regional node involvement. PROCEDURE: Patients <40 years of age with Ewing sarcoma or peripheral primitive neuroectodermal tumor (PNET) reported to the SEER database from 1973 to 2008 were evaluated based on the presence (n = 91) or absence (n = 1,361) of regional node involvement. Patient characteristics were analyzed using Fisher exact tests. Overall survival was estimated by Kaplan-Meier methods and evaluated using log-rank tests and Cox models. RESULTS: Patients with regional node involvement were more likely to have extraskeletal primary tumors (65.9% vs. 31.2%; P < 0.001) and axial tumors (71.1% vs. 59.6%; P = 0.03) compared to patients without regional node involvement. The incidence of regional node involvement was 12.4% for patients with extraskeletal primary tumors compared to 3.2% for patients with skeletal tumors. Five-year overall survival from diagnosis was inferior for patients with regional node involvement compared to those without regional node involvement (45.9% vs. 60.3%; P < 0.001). On multivariate analysis, regional node involvement was predictive of inferior overall survival independent of age, metastatic status, tumor site, and soft tissue origin (hazard ratio 1.59; 95% CI 1.16-2.19). CONCLUSIONS: Patients with extraskeletal Ewing sarcoma should undergo evaluation for regional node involvement. If validated, our findings indicate that regional node involvement may be an independent adverse prognostic factor in Ewing sarcoma, and potentially useful in risk-stratifying patients with otherwise localized disease.