PRIOR CONCURRENT THERAPY: Biologic therapy: No prior thalidomide No other concurrent biologic therapy for cancer Chemotherapy: No more than 1 prior chemotherapy regimen At least 3 weeks since prior chemotherapy (2 weeks for vincristine and 6 weeks for nitrosoureas) No other concurrent chemotherapy for cancer Endocrine therapy: See Disease Characteristics No concurrent endocrine therapy for cancer Radiotherapy: See Disease Characteristics No concurrent radiotherapy for cancer Surgery: See Disease Characteristics No concurrent surgery for cancer Other: Recovered from prior therapy No other concurrent investigational drugs for cancer