OBJECTIVES: I. Compare survival of patients under age 65 with myeloma treated with standard ABCM (doxorubicin, carmustine, cyclophosphamide, melphalan) vs. intensive C-VAMP (cyclophosphamide, vincristine, doxorubicin, methylprednisolone) followed by high-dose melphalan (with or without total-body irradiation) with bone marrow and peripheral blood stem cell support, both with IFN-A maintenance. II. Compare the toxicity profiles of the 2 treatment arms. III. Compare the 2 treatment arms with respect to quality of life and health economics issues. IV. Investigate cellular changes by means of linked morphology, phenotype, and cytogenetics studies before and after treatment and at relapse.