PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior chemotherapy regimens containing topotecan, irinotecan, or docetaxel At least 4 weeks since other prior chemotherapy (6 weeks since prior nitrosoureas, melphalan, or mitomycin) Endocrine therapy: Not specified Radiotherapy: See Disease Characteristics At least 4 weeks since prior wide field radiotherapy No prior radiotherapy to greater than 20% of bone marrow Surgery: See Disease Characteristics Recovered from any prior surgery Other: No other concurrent investigational agents