Irinotecan in Treating Patients With Stage IV or Recurrent Soft Tissue Sarcoma

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed recurrent or stage IV (metastatic or locally advanced) unresectable soft tissue sarcoma Patients with soft tissue Ewing's sarcoma, Kaposi's sarcoma, sarcoma of the bone, and mesothelioma are not eligible Must have failed at least one, but no more than two, prior chemotherapy regimens, one of which contained doxorubicin either as adjuvant therapy or first-line therapy for metastatic disease Bidimensionally measurable disease on x-ray, MRI or CT scan, or physical exam (outside of previously irradiated area) No CNS metastases PATIENT CHARACTERISTICS: Age: 18 and over Performance status: SWOG 0-2 Life expectancy: Not specified Hematopoietic: Platelet count at least lower limit of normal WBC at least 3,500/mm3 OR Absolute neutrophil count at least 1,750/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL AST no greater than 3 times upper limit of normal (ULN) (no greater than 5 times ULN with liver tumor involvement) Renal: Creatinine less than ULN OR Creatinine clearance greater than 60 mL/min Calcium less than ULN Cardiovascular: No myocardial infarction within past 6 months No congestive heart failure requiring therapy Other: Not pregnant or nursing Fertile patients must use effective contraception No physical, mental, or emotional disorders No other prior malignancy within the past 5 years, except: Adequately treated basal or squamous cell skin cancer Carcinoma in situ of the cervix Adequately treated stage I or II cancer in complete remission No active or uncontrolled infection HIV negative No known Gilbert's syndrome No uncontrolled diabetes (random blood sugar at least 200 mg) PRIOR CONCURRENT THERAPY: Biologic therapy: Prior biologic response modifier therapy allowed Chemotherapy: See Disease Characteristics No prior irinotecan or topotecan No other concurrent chemotherapy Endocrine therapy: No concurrent hormonal therapy Radiotherapy: See Disease Characteristics At least 3 weeks since prior radiotherapy and recovered No concurrent radiotherapy Surgery: At least 4 weeks since prior surgery and recovered