PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since prior biologic therapy Chemotherapy: See Disease Characteristics At least 4 weeks since prior chemotherapy and recovered No prior treatment with aminocamptothecin Endocrine therapy: At least 4 weeks since prior endocrine therapy Radiotherapy: At least 4 weeks since prior radiotherapy and recovered No prior radiotherapy to site(s) of measurable disease used on this trial No prior radiotherapy to more than 25% of marrow-bearing areas Surgery: At least 4 weeks since prior surgery