Prognostic markers in chronic lymphocytic leukemia: a comprehensive review

The clinical course of individual CLL patients is highly variable, with life expectancies ranging from months to decades. Importantly, a significant subset of patients presents with low grade CLL, but will nevertheless develop a more aggressive and life-threatening disease. As these patients may potentially benefit from early treatment, it is crucial to assess patients' prognosis at diagnosis, allowing individual risk-adapted therapy. Reliable predictions of prognosis in an early stage of the disease have long been lacking in the clinical workup of CLL patients. During the last decades many efforts have been made to identify prognostic markers in CLL, resulting in a plethora of reports describing the predictive value of different parameters with regard to overall survival, disease progression and response to therapy. In this review, we attempt to provide an overview of the literature and we discuss the most important prognostic markers in CLL, from clinical staging systems and serum markers over proliferation markers and cytogenetics to more recent markers like the IgV(H) mutation status and its possible surrogate markers. Particular attention is paid to the advantages and drawbacks of all different markers, both from a clinical and from a technical point-of-view, highlighting the accomplishments as well as the remaining challenges in this rapidly evolving area of CLL research. Although the great majority of prognostic markers is not included in current international treatment guidelines, several of these markers deserve to be evaluated in prospective clinical trials and may eventually contribute to an improved clinical management of CLL patients.