Abstract
Purpose
Ewings sarcoma (EWS) is the second most common primary malignancy of bone. Five-year survival ranges between 50 and 70% for patients who present with localized disease. EWS occurs in both axial and appendicular locations. The prognostic importance of anatomic location (axial vs. appendicular) is unclear. The purpose of this study is to report a single institution experience in the management of patients with EWS, and to investigate anatomic location as a prognostic factor.
Method
After ethics board approval, we searched our prospective sarcoma database for all EWS patients treated between 1989 and 2007. Sixty-seven patients with adequate follow-up were identified and records were reviewed. Axial bone EWS was defined as originating from the spine, sacrum, pelvis, scapula, clavicle, or rib cage. Appendicular bone EWS was defined as disease from any bone in the extremities. Axial soft tissue EWS was defined as originating in the head, neck, or torso. Appendicular soft tissue EWS originated from the extremeties. Sixty-six (99%) patients received chemotherapy. Definitive local treatment was by surgical resection whenever possible (n=44). Radiation therapy (RT) was used for unresectable lesions (n=10) or to treat positive margins (n=10). The primary outcome measure was overall survival (OS) measured from the date of diagnosis to the date of death or last follow-up and estimated using the Kaplan-Meier method. Univariate and multivariate analyses were performed. Besides anatomic location, the variables of tumor size, metastases at diagnosis, treatment with radiation, and surgical margins were studied.
Results
Forty-one patients were male and 26 were female. The mean age at diagnosis was 26.9 years (12.4–77.9). Fifteen presented with metastases as diagnosis. Thirty-four (51%) patients had axial EWS and 33 (49%) patients had appendicular EWS. OS for the whole group was 64% at 2 years and 47% at 5 years. OS in patients with axial EWS was 44% at 2 years and 29% at 5 years. OS in patients with appendicular EWS was 84% at 2 years and 66% at 5 years. OS was thus significantly worse for patients with axial EWS (p=0.002). After adjusting for pre-treatment variables (size and metastases at diagnosis), axial location remained associated with decreased OS with a hazard ratio 3.11 (95% CI: 1.41 to 6.84; p=0.005). After adjusting for pre-treatment and treatment variables (XRT and surgical margins), axial location was still associated with decreased OS with a hazard ratio of 4.73 (95% CI: 0.87 to 25.7). The association did not reach statistical significance (p=0.072).
Conclusion
Our data demonstrate that axial location predicts poor prognosis in EWS. This risk remains after adjusting for pre-treatment variables, but is less strong after adjustment for treatment variables, possibly due to sample size. Axial EWS may possess an intrinsically more aggressive phenotype. Additional clinical and basic scientific investigations are required to address this hypothesis.
