Chronic lymphocytic leukemia (CLL) is one of the chronic lymphoproliferative disorders (lymphoid neoplasms). It is characterized by a progressive accumulation of functionally incompetent lymphocytes, which are monoclonal in origin.
CLL is considered to be identical (ie, one disease at different stages) to the mature (peripheral) B cell neoplasm small lymphocytic lymphoma (SLL), one of the indolent non-Hodgkin lymphomas. The term CLL is used when the disease manifests primarily in the bone marrow and blood while the term SLL is used when involvement is primarily nodal. (See "Pathologic features, diagnosis, and differential diagnosis of chronic lymphocytic leukemia".)
Most patients undergoing chemotherapy for CLL will have an initial complete or partial response. However, with the exception of some of those treated with hematopoietic cell transplantation, disease relapse invariably occurs after treatment has been discontinued. The treatment of relapsed or refractory CLL/SLL will be reviewed here. The initial treatment of CLL, the use of hematopoietic cell transplantation in CLL, and the management of complications of CLL are discussed separately. (See "Overview of the treatment of chronic lymphocytic leukemia" and "Hematopoietic cell transplantation in chronic lymphocytic leukemia" and "Overview of the complications of chronic lymphocytic leukemia".)
IDENTIFYING RELAPSED OR REFRACTORY DISEASE
Definitions — The International Workshop on CLL (IWCLL) response criteria are presented separately. (See "Evaluating response to treatment of chronic lymphocytic leukemia".)
●Relapsed disease occurs in patients who have previously achieved either a complete or partial remission by these criteria but then develop progressive disease after a period of six months or more.