Radiotherapy in Ewing's sarcoma: Results of the GPO studies CESS 81 and CESS 86

In CESS 81 the rate of local recurrences was high particularly in patients with radiation for local control. To improve the safety of local control, in the follow-up study CESS 86 chemotherapy for high risk patients was intensified. The combination of surgery with postoperative radiation was favoured when possible, local control was brought forward from week 18 to week 9, the dosis of postoperative radiotherapy was increased from 36 to 46 Gy, and a radiation planning center was established for centralized planning of radiotherapy on the basis of tumor extension at diagnosis. In addition patients with radiation were randomized for conventional fractionation or a scheme of accelerated split course hyperfractionation with simultaneous chemotherapy. Preliminary results of 76 CESS 86 patients (incl. pilot phase), show a lowered rate of local reccurrences compared to CESS 81: 6% local reccurrences in patients with resection and postoperative radiation and 15% local reccurrences in patients with radiation. With selection of patients with small and chemoresponsive tumors for radiotherapy no longer a disadvantage was seen for patients with radiotherapy concerning the safety of local control.