S0115, High-Dose Melphalan and Autologous Peripheral Stem Cell Transplantation in Treating Patients With Multiple Myeloma or Primary Systemic Amyloidosis

DISEASE CHARACTERISTICS: * At least 1 of the following diagnoses: * Multiple myeloma * Stage II or III disease * At least 1 of the following must be present: * Serum M-protein of IgG, IgA, IgD, IgE greater than 1.0 g/dL * Urinary M-protein (Bence-Jones) at least 200 mg/24 hours * No IgM peaks except in patients who have physiologic criteria to support a diagnosis of multiple myeloma (e.g., bony lesions, myeloma kidney-cast nephropathy, absence of adenopathy \[unless pathology-proven to be plasma cell infiltration\]) * No monoclonal gammopathy of undetermined significance * No indolent or smoldering myeloma * No disease progression on prior thalidomide or dexamethasone * Histologically confirmed primary systemic amyloidosis * No senile, secondary, localized, dialysis-related, or familial amyloidosis * No severe cardiac involvement * No pre-exertional syncope, ventricular arrhythmia, or symptomatic pleural effusions associated with cardiac involvement * Light Chain Deposition Disease alone or in combination with multiple myeloma meeting the following criteria: * Deposition of granular material containing free light chains/immunoglobulins that did not bind Congo red * Evidence of plasma cell dyscrasia (i.e., monoclonal gammopathy in the serum or urine by immunofixation electrophoresis and/or clonal plasmacytosis) on bone marrow biopsy by immunohistochemistry and/or elevated serum-free light chain concentratio…