Irinotecan in Treating Patients With Newly Diagnosed Ewing's Sarcoma

DISEASE CHARACTERISTICS: Histologically confirmed Ewing's tumor Ewing's sarcoma or peripheral primitive neuroectodermal tumor of bone or soft tissue High-risk disease (R3), defined as metastases at extrapulmonary/pleural sites Newly diagnosed disease Measurable primary and/or metastatic disease At least one bidimensionally measurable lesion Concurrent enrollment on EURO-Ewing99 clinical trial required PATIENT CHARACTERISTICS: No abnormal cardiac function, including any of the following: Fractional shortening < 29% Ejection fraction < 40% Glomerular filtration rate ≥ 60mL/min Not pregnant Negative pregnancy test Fertile patients must use effective contraception during and for 3 months after completion of study treatment No prior or current history of chronic diarrhea, bowel obstruction, sub obstruction, Crohn's disease, or ulcerative colitis No other medical, psychiatric, or social condition incompatible with the study treatment PRIOR CONCURRENT THERAPY: No prior chemotherapy No more than 45 days since prior definitive biopsy