PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: See Disease Characteristics At least 3 weeks since prior chemotherapy (6 weeks for mitomycin or nitrosourea) and recovered No more than 240 mg/m2 total cumulative dose of prior doxorubicin Endocrine therapy: Prior octreotide allowed Recovered from prior octreotide Radiotherapy: At least 3 weeks since prior radiotherapy and recovered Surgery: Not specified