Dexamethasone With or Without Thalidomide in Treating Patients With Newly Diagnosed Multiple Myeloma

DISEASE CHARACTERISTICS: * Newly diagnosed symptomatic multiple myeloma confirmed by the following: * Bone marrow plasmacytosis with at least 10% plasma cells or sheets of plasma cells or biopsy-proven plasmacytosis * Monoclonal protein (M protein) at least 1.0 g/dL on serum protein electrophoresis or at least 200 mg of monoclonal light chain on a 24-hour urine protein electrophoresis * No smoldering myeloma or monoclonal gammopathy of undetermined significance PATIENT CHARACTERISTICS: Age: * 18 and over Performance status: * ECOG 0-2 Life expectancy: * Not specified Hematopoietic: * Absolute neutrophil count greater than 1,000/mm\^3 * Platelet count greater than 50,000/mm\^3 * Hemoglobin greater than 7 g/dL Hepatic: * Bilirubin no greater than 1.5 mg/dL * ALT and AST no greater than 2.5 times upper limit of normal Renal: * Creatinine less than 3 mg/dL Cardiovascular: * No prior or concurrent deep venous thrombosis Other: * Prior malignancy allowed provided the following criteria are met: * Received prior treatment with curative intent * Free of disease for the time period appropriate for cure of the specific cancer * No grade 2 or greater peripheral neuropathy due to other medical conditions * No active infection * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use 1 highly effective method and 1 additional method of contraception for 1 month before, during, and for 4 weeks after study for women and effective barrier contraception for men during and for 4 weeks after study participation PRIOR CONCURRENT THERAPY: Biologic therapy: * No prior biologic therapy for multiple myeloma * No other concurrent biologic therapy for multiple myeloma Chemotherapy: * No prior chemotherapy for multiple myeloma * No other concurrent chemotherapy for multiple myeloma Endocrine therapy: * More than 6 months since prior systemic dexamethasone or glucocorticoids * No concurrent corticosteroids Radiotherapy: * At least 4 weeks since prior palliative, localized radiotherapy * Concurrent palliative, localized radiotherapy allowed at the physician's discretion Surgery: * Not specified Other: * No prior systemic therapy for multiple myeloma, except bisphosphonates * No concurrent anticoagulant therapy for deep vein thrombosis * No concurrent barbiturates or alcohol (thalidomide arm)