Prediction of Response and Prognostic Factors for Ewing Family of Tumors in a Low Incidence Population

Purpose: There is some unknown reason Ewing family of tumors (EFTs) is much less common on Asia and Africa than in the Western Caucasian population. This study analyzed the prediction of response and prognostic factors for Ewing family of tumors (EFTs) in an Asian population with a low incidence.

Methods: We retrospectively reviewed 94 patients with EFTs between 1978 and 2006. Fifteen patients received local therapy only. Statistical analyses were performed for 79 patients, including those who received systemic chemotherapy, to identify factors related to chemotherapy responsiveness, event-free survival, and overall survival.

Results: Of the 79 patients whose records were analyzed, the 5-year event-free rate and overall survival (OS) rate were 41 and 54%, respectively. The response rate to first-line chemotherapy was 61% in 70 patients with assessable lesions. A significant predictor of response was existence of a non-pelvic primary tumor (P = 0.04). Significant prognostic factors for OS were age, performance status, and metastases at the time of diagnosis (P < 0.01, respectively). Fifty-four patients had disease progression or recurrence after first-line treatment. The time to progression was 3.4 months after salvage treatment. Progression during first-line treatment was significantly associated with time to progression after salvage treatment (P = 0.01). All patients treated without chemotherapy in first-line treatment were recurred with poor prognosis.

Conclusion: A non-pelvic primary tumor was a favorable predictor of responsiveness to chemotherapy. Chemo-resistant patients might less benefit from second line chemotherapy. Chemotherapy in first-line treatment should not be omitted, even if primary tumor was extirpated completely.