DISEASE CHARACTERISTICS:

• Histologically confirmed rhabdomyosarcoma, undifferentiated sarcoma, or ectomesenchymoma

  • First relapse or first occurrence of disease progression

• Unfavorable-risk patients eligible for study window therapy with irinotecan and vincristine meeting the following criteria:

  • Unfavorable risk defined by any of the following:

    • Embryonal histology with stage I or group I at initial diagnosis with distant recurrence or with local or regional recurrence after prior cyclophosphamide
    • Embryonal histology with initial stage II, III, or IV or group II, III, or IV with any relapse pattern
    • Alveolar histology with any stage or group at initial diagnosis
  • At least unidimensionally measurable disease
  • No prior irinotecan
  • Bone marrow must not be only site of relapse OR

• Unfavorable-risk patients ineligible for study window therapy with irinotecan meeting the following criteria:

  • Either no measurable disease OR patient received prior irinotecan
  • Bone marrow as only site of relapse allowed OR

• Favorable-risk patients meeting the following criteria:

  • Initial botryoid histology (any stage, any group, or any pattern of relapse)
  • Embryonal histology if either stage I or group I (with either local or regional recurrence)
  • No prior cyclophosphamide
• No CNS metastases

PATIENT CHARACTERISTICS:

Age:

• Under 21 at time of initial diagnosis

Performance status:

• ECOG 0-2
• Zubrod 0-2

Life expectancy:

• At least 2 months

Hematopoietic:

• Absolute neutrophil count at least 750/mm^3
• Platelet count at least 75,000/mm^3 (transfusion independent)
• Hemoglobin at least 10.0 g/dL (red blood cell transfusion allowed)

Hepatic:

• Bilirubin no greater than 1.5 times normal
• SGPT less than 2.5 times normal

Renal:

• Creatinine no greater than 1.5 times normal OR
• Creatinine clearance or radioisotope glomerular filtration rate at least 70 mL/min

Cardiovascular:

• Shortening fraction at least 27% by echocardiogram OR
• Ejection fraction at least 50% by MUGA
• No prior ischemic heart disease

Other:

• Seizure disorder allowed if well controlled by anticonvulsants
• No CNS toxicity greater than grade 2
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No prior myeloablative therapy with stem cell transplantation
• At least 1 week since prior antineoplastic biologic agent
• At least 1 week since prior growth factor(s)
• Recovered from prior immunotherapy
• No concurrent immunomodulating agents

Chemotherapy:

• See Disease Characteristics
• See Biologic therapy
• No more than 1 prior chemotherapy regimen
• No prior doxorubicin or daunorubicin
• At least 2 weeks since prior myelosuppressive chemotherapy (4 weeks for nitrosoureas) and recovered
• No other concurrent anticancer chemotherapy

Endocrine therapy:

• Concurrent corticosteroid therapy allowed

Radiotherapy:

• At least 2 weeks since prior small-port radiotherapy.
• At least 6 months since prior radiotherapy to 50% or more of pelvis
• At least 6 weeks since other prior substantial radiotherapy to bone marrow
• Recovered from prior radiotherapy
• Concurrent radiotherapy to localized painful lesions allowed provided at least 1 measurable lesion is not irradiated
• No concurrent intensity-modulated radiotherapy

Surgery:

• Not specified