Topotecan in Treating Patients With Recurrent or Refractory Cancer of the Uterus

DISEASE CHARACTERISTICS: Histologically proven recurrent or refractory carcinosarcoma (mixed mesodermal tumors) of the uterus Measurable disease PATIENT CHARACTERISTICS: Age: Not specified Performance Status: GOG 0-2 Life Expectancy: Not specified Hematopoietic: Platelet count at least 100,000/mm3 Absolute granulocyte count at least 1,500/mm3 Hepatic: Bilirubin no greater than 1.5 times upper limit of normal (ULN) SGOT no greater than 3 times ULN Alkaline phosphatase no greater than 3 times ULN Renal: Creatinine no greater than 1.5 mg/dL Creatinine clearance greater than 20 mL/min Other: No invasive malignancies within the past 5 years except nonmelanomatous skin cancer No significant infection PRIOR CONCURRENT THERAPY: Biologic therapy: At least 3 weeks since prior biologic therapy Chemotherapy: At least 3 weeks since prior chemotherapy and recovered No prior topotecan or camptothecin therapy No more than 1 prior chemotherapy regimen (either single or combination chemotherapy) Endocrine therapy: At least 3 weeks since prior endocrine therapy Radiotherapy: At least 3 weeks since prior radiotherapy and recovered Surgery: Prior surgery allowed and recovered