PROGNOSTIC FEATURES OF EWING SARCOMA ON PLAIN RADIOGRAPH AND COMPUTED-TOMOGRAPHY SCAN AFTER INITIAL TREATMENT - A PEDIATRIC-ONCOLOGY-GROUP STUDY (8346)

Background. The authors studied the short-term changes in the plain ra diographic and computed tomography (CT) appearance of Ewing sarcoma fo r indicators of decreased survival or future disease progression. Meth ods. The authors evaluated CT scans and plain radiographs of the prima ry tumor site from 105 patients with Ewing sarcoma at diagnosis (prebi opsy), after induction chemotherapy (13 weeks), and after radiation th erapy (20 weeks). Results. Data suggest an association between postind uction CT findings of medullary involvement, cortical destruction, lys is, permeation, and unhealed pathologic fracture and decreased surviva l. On the postradiation scans, only medullary involvement was associat ed with worsened survival. No plain radiographic features were signifi cant at any time. Absolute greatest tumor dimension was not significan tly related to survival or tumor progression. The Cox model suggested that fractional change in greatest tumor dimension on CT at the time p oints studied relative to the prebiopsy CT was correlated to survival. Log-rank testing did not corroborate this finding. All significant as sociations appeared to result from adverse outcomes in small subgroups . Conclusions. Our data suggest that CT obtained immediately after ind uction chemotherapy and radiation may have some limited use in predict ing the long-term prognosis of patients with Ewing sarcoma.