Prognostic features of Ewing sarcoma on plain radiograph and computed tomography scan after initial treatment. A Pediatric Oncology Group study (8346).

Abstract

The authors studied the short-term changes in the plain radiographic and computed tomography (CT) appearance of Ewing sarcoma for indicators of decreased survival or future disease progression. The authors evaluated CT scans and plain radiographs of the primary tumor site from 105 patients with Ewing sarcoma at diagnosis (prebiopsy), after induction chemotherapy (13 weeks), and after radiation therapy (20 weeks). Data suggest an association between postinduction CT findings of medullary involvement, cortical destruction, lysis, permeation, and unhealed pathologic fracture and decreased survival. On the postradiation scans, only medullary involvement was associated with worsened survival. No plain radiographic features were significant at any time. Absolute greatest tumor dimension was not significantly related to survival or tumor progression. The Cox model suggested that fractional change in greatest tumor dimension on CT at the time points studied relative to the prebiopsy CT was correlated to survival. Log-rank testing did not corroborate this finding. All significant associations appeared to result from adverse outcomes in small subgroups. Our data suggest that CT obtained immediately after induction chemotherapy and radiation may have some limited use in predicting the long-term prognosis of patients with Ewing sarcoma.