Melphalan, Thalidomide, and Dexamethasone in Treating Patients With Newly Diagnosed, Previously Untreated Primary Systemic Amyloidosis

DISEASE CHARACTERISTICS: * Diagnosis of primary systemic (AL) amyloidosis within the past 12 months * High- or low-risk disease, determined by the extent of systemic organ involvement with disease and patient age PATIENT CHARACTERISTICS: Age * 18 and over Performance status * SWOG 0-3 Life expectancy * Not specified Hematopoietic * Not specified Hepatic * Not specified Renal * Not specified Cardiovascular * No New York Heart Association class III or IV congestive heart failure * No restrictive cardiomyopathy requiring oxygen * No myocardial infarction within the past 6 months * No symptomatic cardiac arrhythmia within the past 60 days Other * No other active malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer, carcinoma in situ of the cervix, or adequately treated stage I cancer in complete remission PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * No prior chemotherapy for AL amyloidosis Endocrine therapy * Not specified Radiotherapy * Not specified Surgery * Not specified Other * No other prior or concurrent therapy for AL amyloidosis