Chronic lymphocytic leukemia (CLL) is a lymphoproliferative disorder that accounts for approximately 30 % of adult leukemias and 25 % of Non-Hodgkin lymphomas (NHL). It is the most common form of leukemia in the western world (incidence 3-5/100 000). Elderly people are mainly affected, median age at diagnosis is around 70 years and there is a slight predominance in men. The etiology of the disease is unknown. The initial symptoms are nonspecific. Cervical lymphadenopathy and splenomegaly followed by general fatigue are seen most commonly. Other possible symptoms include night sweats, fever, loss of weight (so-called B symptoms) and frequent infections. Several patients develop autoimmune complications as autoimmune hemolytic anemia (AIHA) or immune thrombocytopenia (ITP). To confirm the diagnosis more than 5000 B-lymphocytes/µl need to be present. The expression of the typical surface markers CD5, CD19, and CD23 has to be confirmed by flow cytometry. Imaging studies as X-ray of the chest, ultrasound of the abdomen, or CT scan are used to assess the degree of lymphadenopathy or organomegaly. A bone marrow biopsy is not mandatory for the diagnosis. According to the European Binet staging system, CLL is divided into 3 stages (A, B and C). Patients in Binet stage A have 0 to 2 areas of node or organ enlargement with normal levels of hemoglobin and platelets. Binet stage B patients have 3 to 5 areas of node or organ enlargement and normal or slightly decreased levels of hemoglobin and platelets. Binet stage C patients have anemia (hemoglobin < 10 g/dl) and/or thrombocytopenia (platelet counts < 100 000/µl), with or without lymphadenopathy or organomegaly. As there is no survival benefit associated with early intervention, asymptomatic patients with early stage CLL (Binet stage A and B) are usually not treated but are followed on a "watch and wait" principle. Treatment indications include stage Binet C or signs of an active disease as rapidly progressive lymphadenopathy or organomegaly together with physical limitation, B symptoms that cannot be tolerated, rapidly deteriorating blood values, or rapidly increasing leukocyte counts. The patient's physical condition has major impact on the treatment decision. Currently immunochemotherapy with fludarabine, cyclophosphamide and the CD20-antibody rituximab (FCR) is the standard of care in previously untreated and physically fit CLL-patients. An alternative regimen is the combination of bendamustine and rituximab (BR). Physically compromised patients can be treated with the oral drug chlorambucil or with bendamustine with or without rituximab. Due to high morbidity and mortality, allogeneic stem cell transplantation is limited to a small group of patients and should be discussed in a high-risk situation, such as 17p deletion, lack of response to standard therapy or early relapse.
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