To improve the prognosis of patients with metastatic or high-risk localized sarcoma in first CR, we explored the role of consolidation therapy with megatherapy and hematopoietic rescue. From 1986 to 1995, of 72 patients with Ewing's sarcoma from three pediatric departments, 30 were diagnosed as high-risk patients. Of these 30 patients, six did not achieve complete remission and four refused megatherapy and received multimodal treatment (chemotherapy + surgery and/or radiotherapy). The remaining 20 patients received megatherapy. There were 15 males and five females with a median age of 10.8 years (range 2-18 years). Five patients had metastatic disease at initial diagnosis, nine patients had primary tumor in the pelvis and 13 had a tumor volume greater than 100 ml. Overall disease-free survival was 62.7+/-11%; 40+/-21.9% for those with metastatic disease, 76.2+/-12.2% for those with tumor volume greater than 100 ml and 64.8+/-16.5% for those with tumor in pelvic bones. In conclusion, megatherapy has improved the outcome of this group of patients relative to that expected following conventional therapy.