Comparative evaluation of local control strategies in localized Ewing sarcoma of bone: a report from the Children's Oncology Group

Abstract

Background: Patients with Ewing sarcoma require local primary tumor control with surgery, radiation, or both. The optimal choice of local control for overall and local disease control remains unclear.

Methods: Patients with localized Ewing sarcoma of bone who were treated on 3 consecutive protocols with standard-dose, 5-drug chemotherapy every 3 weeks were included (n=465). Propensity scores were used to control for differences between local control groups by constructing multivariate models to assess the impact of local control type on clinical endpoints (event-free survival [EFS], overall survival, local failure, and distant failure) independent of differences in their propensity to receive each local control type.

Results: Patients who underwent surgery were younger (P=.02) and had more appendicular tumors (P<.001). Compared with surgery, radiation had higher unadjusted risks of any event (hazard ratio [HR], 1.70; 95% confidence interval [CI], 1.18-2.44), death (HR, 1.84; 95% CI, 1.18-2.85), and local failure (HR, 2.57; 95% CI, 1.37-4.83). On multivariate analysis, compared with surgery, radiation had a higher risk of local failure (HR, 2.41; 95% CI, 1.24-4.68), although there were no significant differences in EFS (HR, 1.42; 95% CI, 0.94-2.14), overall survival (HR, 1.37; 95% CI, 0.83-2.26), or distant failure (HR, 1.13; 95% CI, 0.70-1.84) between local control groups.

Conclusions: In this large group of similarly treated patients, choice of the mode of local control was not related significantly to EFS, overall survival, or distant failure, although the risk of local failure was greater for radiation compared with surgery. These data support surgical resection when appropriate, whereas radiotherapy remains a reasonable alternative in selected patients.

Keywords: Ewing sarcoma; local control; propensity score; radiation; surgery.

Figure 1

CONSORT diagram of patient selection for analytic cohort.

Figure 2

A. Propensity scores for definitive radiation alone according to actual mode of local control received. B. Propensity scores for definitive surgery alone according to actual mode of local control received.

Figure 2

A. Propensity scores for definitive radiation alone according to actual mode of local control received. B. Propensity scores for definitive surgery alone according to actual mode of local control received.

Figure 3

A. Unadjusted cumulative incidence of distant failure (either isolated distant failure or combined local plus distant failure) as a first event according to mode of local control. B. Unadjusted cumulative incidence of local failure (either isolated local failure or combined local plus distant failure) as a first event according to mode of local control.

Figure 3

A. Unadjusted cumulative incidence of distant failure (either isolated distant failure or combined local plus distant failure) as a first event according to mode of local control. B. Unadjusted cumulative incidence of local failure (either isolated local failure or combined local plus distant failure) as a first event according to mode of local control.