The identification of prognostic factors has greatly facilitated the rational choice of therapies in individual patients. Intensive chemotherapy, supplemented with radiation and surgery, has increased the remission rate of patients with widespread disease. The persistence of microscopic foci of malignant cells, however, remains a difficult hurdle for long-term disease-free survival. Highly toxic myeloablative therapies have had at most a modest impact on the overall cure rate of poor-risk patients. The use of novel biological therapies has provided new information on the mechanisms and potentials of immune-mediated tumor cytotoxicity. Timely clinical trials are needed to test their role in adjuvant treatment of occult microscopic disease.