OUTLINE: This is a randomized, multicenter study. Patients are stratified according to prior therapy (adjuvant interferon vs chemotherapy for advanced disease vs both vs none), ECOG performance status (0 vs 1), and number of organ sites involved (1 vs more than 1). Patients are randomized into 1 of 3 treatment arms. (Arm III closed to accrual as of 11/30/1998.)