Small lymphocytic lymphoma (SLL) and chronic lymphocytic leukemia (CLL) are in the midst of a period of huge change resulting from advances on several fronts. One important development is the appreciation that SLL and CLL are two manifestations of the same disorder. Throughout this review, therefore, it should be assumed that SLL is managed in a similar manner to CLL, although the studies drawn upon and recommendations made will be based mainly on publications on the diagnosis and therapy for CLL.
There have been major advances in our understanding both of the pathophysiology of CLL/SLL and of the mechanism by which the disease becomes resistant to conventional therapies. This has coincided with the application of novel approaches to define remissions, including the use of modern imaging techniques, which have never previously been applied in CLL, and the development of techniques to detect minimal residual disease, particularly by multiparameter flow cytometry. To some extent a major driver of these changes has been the development of novel therapeutic approaches which yield higher proportions of complete remissions. We have now moved from standard therapies that achieve complete responses in less than 10% of patients to novel approaches that result in greater than 70% complete responses. There is now the prospect of achieving response rates which for other hematopoietic malignancies are associated with a prolongation in survival – and even cures! Treatment paradigms are evolving rapidly towards risk stratification by molecular prognostic factors and tailoring therapy to an individual patient's disease.