ABSTRACT
I. INTRODUCTION Chronic lymphocytic leukemia (CLL) is the most common leukemia in the Western World, and the incidence of this disease is increasing yearly. CLL generally follows an indolent clinical course affecting mainly elderly patients, with a median age at presentation of greater than 65 years. Many such patients will not require therapy. However, the disease is heterogeneous, and some patients have a more aggressive clinical course. A number of clinical and biochemical features can be used to identify patients likely to have a more aggressive clinical course. In addition, 40% of patients with CLL are younger than age 60, and 12% are younger than age 50. These patients almost invariably die of their disease or its complications. In the last 10 years, several new drugs have been shown to be effective in CLL, and in the United States, fludarabine has emerged as the treatment of choice. However, to date, no evidence exists that conventional chemotherapy approaches are cura tive in CLL. Despite the high initial response rates reported with effective agents such as fludarabine, patients invariably relapse, and subsequently resistance to chemotherapy develops. The role of fludarabine in combination with other chemotherapy and/or mono clonal antibody therapy appears promising and is currently under investigation. At present, the only potentially curative treatment for CLL is high-dose (HD) ablative therapy with hematopoietic stem cell support. However, there are many unanswered questions about the different treatment modalities of stem cell transplantation (SCT), and their roles in the management of CLL remain to be established. In particular, patient selection for con sideration of SCT, the timing of SCT in the clinical course of CLL, autologous versus allogeneic SCT, use of nonmyeloablative regimens, and exploitation of the graft versus leukemia effect are currently under investigation.
