PRIOR CONCURRENT THERAPY: Biologic therapy: See Chemotherapy Recovered from prior immunotherapy Chemotherapy: See Disease Characteristics No more than 1 prior chemotherapy regimen (adjuvant and/or metastatic) except for nonmyelosuppressive agents (e.g., signal transduction inhibitors or immunotherapy) At least 3 weeks since prior chemotherapy (6 weeks for nitrosoureas and mitomycin and 4 weeks for carboplatin) and recovered At least 1 year since prior high-dose chemotherapy with marrow or stem cell support No prior total cisplatin dose of more than 300 mg/m2 No prior chemotherapy (for recommended phase II dose) Endocrine therapy: Prior hormonal therapy allowed Radiotherapy: At least 4 weeks since prior radiotherapy and recovered No prior radiotherapy to more than 25% of bone marrow reserve, except for low-dose nonmyelosuppression Surgery: Not specified Other: At least 4 weeks since other prior experimental drugs or anticancer therapy and recovered No other concurrent investigational or anticancer therapy