Prognostic features and therapeutical approaches in B-cell chronic lymphocytic leukemia: an update

In the past few decades important progress has been made in the understanding of chronic lymphocytic leukemia (CLL). Indeed, systematic studies of natural history and prognostic factors have made it possible to predict the outcome of disease. Although clinical stage (i.e. Rai and Binet stages) is the strongest predictor of survival, additional prognostic parameters, including patterns of bone marrow (BM) infiltration, lymphocyte doubling time (LDT), immunophenotype and cytogenetics, have now been identified. Furthermore, criteria of smoldering CLL (i.e. stage A, low lymphocyte count, non-diffuse BM histology, relatively high hemoglobin level, LDT > 12 months) allow identification of a subgroup of patients with indolent course and good prognosis for whom treatment should be delayed, unless progression occurs. Recent meta-analysis of clinical trials has demonstrated no survival advantage for immediate versus referred treatment in low clinical stages. The same considerations apply when comparing combination versus single-drug regimens. Purine analogues like fludarabine, 2'-chlorodeoxyadenosine and 2'-deoxycoformicin are active in CLL. Data on these drugs come from uncontrolled clinical trials; randomized studies are in progress. In addition, some issues concerning the relationship between response and survival, cross-resistance between purine analogues and eradication of the CLL clone, remain still unresolved. There are also increasing data on bone marrow transplants in CLL, although the high treatment-related mortality suggests that this procedure may have some benefit only in selected refractory young CLL patients with adverse features. This review will focus on recent progress in the prognosis and therapy of CLL. Issues that remain controversial will be a matter of discussion.