The clinical course of chronic lymphocytic leukemia (CLL) shows a mark
ed heterogeneity, with a median survival ranging from 2 to 20 years at
different disease stages. This unpredictable course has inspired clin
ical hematologists and oncologists to search for parameters which pred
ict survival and disease progression. This effort resulted in differen
t staging systems, two of which, the Rai and Binet staging systems, ha
ve become most popular because of their simplicity. They identify thre
e major groups of patients with different survival. Since patients at
early stages have a relatively good prognosis, only advanced stages us
ed to be treated by chemotherapy with alkyling agents. With the advent
of potentially curative, but more aggressive treatment options for CL
L, additional prognostic criteria are required to predict the outcome
more precisely, in particular in young patients with early disease. It
is the intent of this review to summarize the current knowledge of bo
th established and new prognostic factors in CLL, some of which might
help to define risk-adapted treatment protocols in the near future.