The Impact of Radiotherapy Dose on Local Control of Ewing's Sarcoma of Bone.

Purpose. Improvements in the systemic management of Ewing's sarcoma of bone over the last 20 years have led to a dramatic improvement in survival. The corollary is that treatment of the primary disease requires re-evaluation, since a significant number of patients still suffer local relapse.Patients. The effect of radiation dose on local control was reviewed in a series of 96 patients treated between 1967 and 1986. Seventy-four had no metastases at presentation (M0), 22 had metastases (M1). The 5-year survival of all patients was 28%, and of M0 patients alone 37%. Although these figures are poor by today's standards, they are consistent with published studies whose patients were enrolled during the same calendar period. Although most deaths occurred by 5 years, survival continued to fall beyond 10 years, which has implications for follow-up in future studies.Results. The local control (LC) rate at 5 years was 56% for all patients and for M0 patients analyzed separately. There was no difference in either LC or survival between the first and second decades of the study. Primary site was a significant determinant of survival and local control, with better outcome for limb tumours compared to pelvic primaries. Chemotherapy also had a major effect on LC. Radiotherapy improved the probability of LC. Omission of radiotherapy, or a dose <40 Gy, was ineffective. In the dose range 40-66 Gy, there was no evidence of a dose-response relationship.