The role of high-dose therapy and autologous stem cell transplantation (ASCT) in the treatment of patients with Ewing's sarcoma (EWS) remains uncertain. From November 1985 to September 1994, 13 patients aged 16-30 years (median 20.5) received high-dose melphalan (HDM) 140-200 mg/m2 +/- 500 cGy TBI followed by ASCT for relapsed/refractory (n = 4), metastatic (n = 2), or non-metastatic (n = 6) EWS, or for peripheral neuroectodermal tumor (PNET) (n = 1). This regimen was well tolerated with no transplant-related mortality and no toxicity requiring life sustaining measures. Three of the four patients treated for relapsed/refractory EWS had progression-free survivals (PFS) less than 5 months. The only long-term survivor of these four patients received HDM while in complete remission following pulmonary irradiation. Both patients with pulmonary metastases at presentation died just 5 and 6 months post-ASCT. All four patients with non-metastatic, bulky (> 8 cm) osseous EWS progressed at a median of 11 months (range 7-22 months) while the two patients with non-bulky EWS remain progression-free 25+ and 28+ months post-HDM/TBI + ASCT. The 19-year-old patient with a PNET of the thoracoabdominal wall relapsed 4 months post-ASCT. Overall, only three of these 13 patients remain progression-free at 25+, 28+, and 108+ months following HDM +/- TBI and ASCT. In conclusion, HDM +/- TBI did not obviously improve the outcome of these 13 patients relative to that expected following conventional dose therapy alone.