Analysis of prognostic factors in Ewing sarcoma family of tumors: Review of St. Jude Children's Research Hospital studies

BACKGROUND. Advances in systemic and local therapies have improved outcomes for patients with the Ewing sarcoma family of tumors (ESFT). As new treatments are developed, a critical review of data from past treatment eras is needed to identify clinically relevant risk groups. METHODS. The authors reviewed the records of 220 patients with ESFT who were treated on protocols at St. Jude Children's Research Hospital from 1979 to 2004. Two treatment eras were defined. Factors predictive of outcome were analyzed to identify distinct risk groups. RESULTS. The median age at diagnosis was 13.7 years (range, 1.1-25.2 years). Metastatic disease was associated with tumors measuring >8 cm (P = .002) and axial location (P = .014). The 5-year overall survival (OS) estimate (63.5% ± 3.5%) did not appear to differ by protocol. Tumor stage and size were found to be the only independent predictors of outcome. Treatment era and type of local control therapy were found to influence the outcome of patients with localized disease. Four risk groups were defined: favorable risk (age <14 years with localized, non-pelvic tumors), intermediate risk (localized, age >14 years, or pelvic tumors), unfavorable-pulmonary (isolated lung metastases), and unfavorable-extrapulmonary (extrapulmonary metastases). The 5-year OS estimates for these groups were 88.1% ± 4.4%, 64.9% ± 5.2%, 53.8% ± 9.4%, and 27.2% ± 7.3%, respectively (P <.001). The incidence of therapy-related leukemia was significantly higher during the second treatment era, when more intensified regimens were used (6.1% ± 2.7% vs 0% ± 0%; P = .005). CONCLUSIONS. Risk stratification schemes such as this should be used to prospectively evaluate novel risk-based therapies. Studies of biologic pathways may help to refine this model.