Richter's transformation in chronic lymphocytic leukemia.

Richter's syndrome (RS) is characterized by the development of high-grade non-Hodgkin's lymphoma (NHL) in a patient with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma. At The University of Texas M.D. Anderson Cancer Center the incidence of RS is 3.9%. The large cells of RS may arise through transformation of the original CLL clone or represent a new neoplasm. RS may be triggered by viral infections, such as Epstein-Barr virus (EBV). Trisomy 12 and chromosome 11 abnormalities, as well as multiple genetic defects, have been described in patients with RS. These abnormalities may cause CLL cells to proliferate and, by facilitating the acquisition of new genetic abnormalities, to transform into RS cells. The therapeutic strategies for RS typically include therapies developed for NHL or acute lymphoblastic leukemia. The reported response rates with these therapies are 5% to 43%, and the median survival duration ranges from 5 to 8 months. The median overall survival duration at our institution of patients with RS is 9.1 months (95% confidence interval, 7.8 to 11 months), and the median failure-free survival duration is 7.1 months (95% confidence interval, 5.1 to 10.4 months). Patients appear to benefit from cytoreductive therapy consisting of chemotherapy and immunotherapy, followed by allogeneic stem cell transplantation, as postremission therapy. As part of a program aiming to cure RS, we are currently conducting a clinical trial of oxaliplatin, fludarabine, and cytarabine in combination with rituximab and recommend postremission therapy, including allogeneic stem cell transplantation in patients with available donors.