Advances in the diagnosis and treatment of chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in adults, accounting for up to 25% of all newly diagnosed leukemia. Many cases of CLL have a non-aggressive course and often do not require treatment, while other cases exhibit rapid progression within several years. Recent advances in the diagnosis of CLL include the identification of several prognostic factors, such as ZAP70 expression and the absence of immunoglobulin gene rearrangements. These prognostic factors may identify subgroups of CLL patients who would benefit from earlier treatment rather than "watchful waiting." New combination treatment regimens that include nucleoside analogs (fludarabine, cladribine, and pentostatin) and monoclonal antibodies (rituximab and alemtuzumab) have resulted in improved rates of complete remissions in newly diagnosed and relapsed CLL patients; many of these are molecular complete remissions. The only known cure for CLL remains allogeneic hematopoietic cell transplantation. Newer conditioning strategies with lower, nonmyeloablative doses of chemotherapy and radiation therapy have made this option available to a broader group of patients, including older and sicker populations. These advances in prognostic factors, chemotherapy regimens, and allogeneic transplantation will likely enable increases in survival for CLL patients.